…ws#15604)

added the ability to specify an external id for the deploy-role as part of the synthesizer config.
this is similar to the existing functionality that allows specifying the external id for the image
and file publishing roles

In order to take advantage of this functionality you would need to customize the bootstrap template. To test this feature I customized the DeploymentActionRole in the bootstrap template to have the `AssumeRolePolicyDocument` as:

```yaml
DeploymentActionRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Statement:
          - Action: sts:AssumeRole
            Condition:
              StringEquals:
                sts:ExternalId: "my-external-id"
            Effect: Allow
            Principal:
              AWS:
                - Fn::Join:
                    - ""
                    - - "arn:"
                      - Ref: AWS::Partition
                      - :iam::1111111111111:root
        Version: "2012-10-17"
      ...
      RoleName:
        Fn::Sub: cdk-${Qualifier}-deploy-role-${AWS::AccountId}-${AWS::Region}
```

I then created a test stack that specified that external id:

```ts
new CdkExternalIdTestStack(app, 'CdkExternalIdTestStack', {
  env: {
    account: '111111111111',
    region: 'us-east-2',
  },
  synthesizer: new cdk.DefaultStackSynthesizer({
    deployRoleExternalId: 'my-external-id',
  }),
});
```
----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

…ws#15604)

added the ability to specify an external id for the deploy-role as part of the synthesizer config.
this is similar to the existing functionality that allows specifying the external id for the image
and file publishing roles

In order to take advantage of this functionality you would need to customize the bootstrap template. To test this feature I customized the DeploymentActionRole in the bootstrap template to have the `AssumeRolePolicyDocument` as:

```yaml
DeploymentActionRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Statement:
          - Action: sts:AssumeRole
            Condition:
              StringEquals:
                sts:ExternalId: "my-external-id"
            Effect: Allow
            Principal:
              AWS:
                - Fn::Join:
                    - ""
                    - - "arn:"
                      - Ref: AWS::Partition
                      - :iam::1111111111111:root
        Version: "2012-10-17"
      ...
      RoleName:
        Fn::Sub: cdk-${Qualifier}-deploy-role-${AWS::AccountId}-${AWS::Region}
```

I then created a test stack that specified that external id:

```ts
new CdkExternalIdTestStack(app, 'CdkExternalIdTestStack', {
  env: {
    account: '111111111111',
    region: 'us-east-2',
  },
  synthesizer: new cdk.DefaultStackSynthesizer({
    deployRoleExternalId: 'my-external-id',
  }),
});
```
----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Allow passing [all STS options](https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRole.html#API_AssumeRole_RequestParameters) to assume role configuration for various CDK roles. 

> The following PR description focuses on Session Tags because it was originally the only option we wanted to add support to. After some thought, we decided to allow all available STS options via a transparent pass-through.

### Prerequisites

- cdklabs/cloud-assembly-schema#33
- cdklabs/cdk-assets#40

### Issue # (if applicable)

Closes #26157 
Fixes #22535

### Reason for this change

Enabling [ABAC](https://docs.aws.amazon.com/IAM/latest/UserGuide/introduction_attribute-based-access-control.html) via STS session tags. From the [AWS docs](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_session-tags.html):


> _“Session Tags are key-value pair attributes that you pass when you assume an IAM role or federate a user in AWS STS. You do this by making an AWS CLI or AWS API request through AWS STS or through your identity provider (IdP). When you use AWS STS to request temporary security credentials, you generate a session. Sessions expire and have [credentials](https://docs.aws.amazon.com/STS/latest/APIReference/API_Credentials.html), such as an access key pair and a session token. When you use the session credentials to make a subsequent request, the [request context](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements_condition.html#AccessPolicyLanguage_RequestContext) includes the [aws:PrincipalTag](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_condition-keys.html#condition-keys-principaltag) context key. You can use the aws:PrincipalTag key in the Condition element of your policies to allow or deny access based on those tags”_

### Description of changes

The CDK creates [4 IAM roles](https://docs.aws.amazon.com/cdk/v2/guide/bootstrapping-env.html#bootstrapping-env-roles) during bootstrap. It then assumes these roles at various phases of the deployment.

- [DeploymentActionRole](https://github.com/aws/aws-cdk/blob/v2.154.1/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml#L429): Assumed when invoking CloudFormation operations such as _Deploy_ and _DescribeStackEvents_.
- [FilePublishingRole](https://github.com/aws/aws-cdk/blob/v2.154.1/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml#L275): Assumed when file assets are uploaded to the bootstrap bucket.
- [ImagePublishingRole](https://github.com/aws/aws-cdk/blob/v2.154.1/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml#L298): Assumed when docker images are published to the bootstrap ECR registry.
- [LookupRole](https://github.com/aws/aws-cdk/blob/v2.154.1/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml#L321): Assumed while performing context lookups.

Each of these roles should be assumable with their own specific session tags, as they server different purposes.

> Note: The [CloudFormationExecutionRole](https://github.com/aws/aws-cdk/blob/v2.154.1/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml#L536) is also created during bootstrap, but the CLI never assumes it, therefore it doesn't need session tags support.

Session tags for each role will be configurable via synthesizer properties (similarly to how `externalId` is [exposed](#15604)) both for the `DefaultStackSynthesizer`, and for a custom synthesizer extending the `StackSynthesizer` class. The new properties will propagate down and will eventually be written to the cloud assembly.

#### `+ manifest.json`

```json
{
  "version": "36.0.0",
  "artifacts": {
    "MyStack.assets": {
      "type": "cdk:asset-manifest",
      "properties": {
        "file": "SeshTagsManifestStack.assets.json",
        "requiresBootstrapStackVersion": 6,
        "bootstrapStackVersionSsmParameter": "/cdk-bootstrap/hnb659fds/version"
      }
    },
    "MyStack": {
      "type": "aws:cloudformation:stack",
      "environment": "aws://unknown-account/unknown-region",
      "properties": {
        "assumeRoleArn": "arn:${AWS::Partition}:iam::${AWS::AccountId}:role/cdk-hnb659fds-deploy-role-${AWS::AccountId}-${AWS::Region}",
          "assumeRoleAdditionalOptions": {
            "Tags": < deployRoleSessionTags > 
          }
        "lookupRole": {
          "arn": "arn:${AWS::Partition}:iam::${AWS::AccountId}:role/cdk-hnb659fds-lookup-role-${AWS::AccountId}-${AWS::Region}",
          "requiresBootstrapStackVersion": 8,
          "bootstrapStackVersionSsmParameter": "/cdk-bootstrap/hnb659fds/version"
          "assumeRoleAdditionalOptions": {
            "Tags": < lookupRoleSessionTags > 
          }
        }
      },
```

#### `+ assets.json`

```json
{
  "version": "36.0.0",
  "files": {
    "9ebfd704f02f99b2711998e6435822b0dbed6e80dcac7e75f339fe894861ac20": {
      "source": {
        "path": "mystack.template.json",
        "packaging": "file"
      },
      "destinations": {
        "current_account-current_region": {
          "assumeRoleArn": "arn:${AWS::Partition}:iam::${AWS::AccountId}:role/cdk-hnb659fds-file-publishing-role-${AWS::AccountId}-${AWS::Region}"
          "assumeRoleAdditionalOptions": {
             "Tags": < fileAssetPublishingRoleSessionTags >
           }
        }
      }
    }
  },
  "dockerImages": {
    "dockerHash": {
      "source": {
        "directory": "."
      },
      "destinations": {
        "current_account-current_region": {
          "assumeRoleArn": "arn:${AWS::Partition}:iam::${AWS::AccountId}:role/cdk-hnb659fds-image-publishing-role-${AWS::AccountId}-${AWS::Region}"
          "assumeRoleAdditionalOptions": {
            "Tags": < imageAssetPublishingRoleSessionTags >
          }
        }
      }
    }
  }
}
```

### Description of how you validated changes

- CLI integration tests.
- CLI and framework unit tests.

### Checklist
- [X] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Allow passing [all STS options](https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRole.html#API_AssumeRole_RequestParameters) to assume role configuration for various CDK roles. 

> The following PR description focuses on Session Tags because it was originally the only option we wanted to add support to. After some thought, we decided to allow all available STS options via a transparent pass-through.

### Prerequisites

- cdklabs/cloud-assembly-schema#33
- cdklabs/cdk-assets#40

### Issue # (if applicable)

Closes aws#26157 
Fixes aws#22535

### Reason for this change

Enabling [ABAC](https://docs.aws.amazon.com/IAM/latest/UserGuide/introduction_attribute-based-access-control.html) via STS session tags. From the [AWS docs](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_session-tags.html):


> _“Session Tags are key-value pair attributes that you pass when you assume an IAM role or federate a user in AWS STS. You do this by making an AWS CLI or AWS API request through AWS STS or through your identity provider (IdP). When you use AWS STS to request temporary security credentials, you generate a session. Sessions expire and have [credentials](https://docs.aws.amazon.com/STS/latest/APIReference/API_Credentials.html), such as an access key pair and a session token. When you use the session credentials to make a subsequent request, the [request context](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements_condition.html#AccessPolicyLanguage_RequestContext) includes the [aws:PrincipalTag](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_condition-keys.html#condition-keys-principaltag) context key. You can use the aws:PrincipalTag key in the Condition element of your policies to allow or deny access based on those tags”_

### Description of changes

The CDK creates [4 IAM roles](https://docs.aws.amazon.com/cdk/v2/guide/bootstrapping-env.html#bootstrapping-env-roles) during bootstrap. It then assumes these roles at various phases of the deployment.

- [DeploymentActionRole](https://github.com/aws/aws-cdk/blob/v2.154.1/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml#L429): Assumed when invoking CloudFormation operations such as _Deploy_ and _DescribeStackEvents_.
- [FilePublishingRole](https://github.com/aws/aws-cdk/blob/v2.154.1/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml#L275): Assumed when file assets are uploaded to the bootstrap bucket.
- [ImagePublishingRole](https://github.com/aws/aws-cdk/blob/v2.154.1/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml#L298): Assumed when docker images are published to the bootstrap ECR registry.
- [LookupRole](https://github.com/aws/aws-cdk/blob/v2.154.1/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml#L321): Assumed while performing context lookups.

Each of these roles should be assumable with their own specific session tags, as they server different purposes.

> Note: The [CloudFormationExecutionRole](https://github.com/aws/aws-cdk/blob/v2.154.1/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml#L536) is also created during bootstrap, but the CLI never assumes it, therefore it doesn't need session tags support.

Session tags for each role will be configurable via synthesizer properties (similarly to how `externalId` is [exposed](aws#15604)) both for the `DefaultStackSynthesizer`, and for a custom synthesizer extending the `StackSynthesizer` class. The new properties will propagate down and will eventually be written to the cloud assembly.

#### `+ manifest.json`

```json
{
  "version": "36.0.0",
  "artifacts": {
    "MyStack.assets": {
      "type": "cdk:asset-manifest",
      "properties": {
        "file": "SeshTagsManifestStack.assets.json",
        "requiresBootstrapStackVersion": 6,
        "bootstrapStackVersionSsmParameter": "/cdk-bootstrap/hnb659fds/version"
      }
    },
    "MyStack": {
      "type": "aws:cloudformation:stack",
      "environment": "aws://unknown-account/unknown-region",
      "properties": {
        "assumeRoleArn": "arn:${AWS::Partition}:iam::${AWS::AccountId}:role/cdk-hnb659fds-deploy-role-${AWS::AccountId}-${AWS::Region}",
          "assumeRoleAdditionalOptions": {
            "Tags": < deployRoleSessionTags > 
          }
        "lookupRole": {
          "arn": "arn:${AWS::Partition}:iam::${AWS::AccountId}:role/cdk-hnb659fds-lookup-role-${AWS::AccountId}-${AWS::Region}",
          "requiresBootstrapStackVersion": 8,
          "bootstrapStackVersionSsmParameter": "/cdk-bootstrap/hnb659fds/version"
          "assumeRoleAdditionalOptions": {
            "Tags": < lookupRoleSessionTags > 
          }
        }
      },
```

#### `+ assets.json`

```json
{
  "version": "36.0.0",
  "files": {
    "9ebfd704f02f99b2711998e6435822b0dbed6e80dcac7e75f339fe894861ac20": {
      "source": {
        "path": "mystack.template.json",
        "packaging": "file"
      },
      "destinations": {
        "current_account-current_region": {
          "assumeRoleArn": "arn:${AWS::Partition}:iam::${AWS::AccountId}:role/cdk-hnb659fds-file-publishing-role-${AWS::AccountId}-${AWS::Region}"
          "assumeRoleAdditionalOptions": {
             "Tags": < fileAssetPublishingRoleSessionTags >
           }
        }
      }
    }
  },
  "dockerImages": {
    "dockerHash": {
      "source": {
        "directory": "."
      },
      "destinations": {
        "current_account-current_region": {
          "assumeRoleArn": "arn:${AWS::Partition}:iam::${AWS::AccountId}:role/cdk-hnb659fds-image-publishing-role-${AWS::AccountId}-${AWS::Region}"
          "assumeRoleAdditionalOptions": {
            "Tags": < imageAssetPublishingRoleSessionTags >
          }
        }
      }
    }
  }
}
```

### Description of how you validated changes

- CLI integration tests.
- CLI and framework unit tests.

### Checklist
- [X] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Allow passing [all STS options](https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRole.html#API_AssumeRole_RequestParameters) to assume role configuration for various CDK roles. 

> The following PR description focuses on Session Tags because it was originally the only option we wanted to add support to. After some thought, we decided to allow all available STS options via a transparent pass-through.

### Prerequisites

- cdklabs/cloud-assembly-schema#33
- cdklabs/cdk-assets#40

### Issue # (if applicable)

Closes #26157 
Fixes #22535

### Reason for this change

Enabling [ABAC](https://docs.aws.amazon.com/IAM/latest/UserGuide/introduction_attribute-based-access-control.html) via STS session tags. From the [AWS docs](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_session-tags.html):


> _“Session Tags are key-value pair attributes that you pass when you assume an IAM role or federate a user in AWS STS. You do this by making an AWS CLI or AWS API request through AWS STS or through your identity provider (IdP). When you use AWS STS to request temporary security credentials, you generate a session. Sessions expire and have [credentials](https://docs.aws.amazon.com/STS/latest/APIReference/API_Credentials.html), such as an access key pair and a session token. When you use the session credentials to make a subsequent request, the [request context](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements_condition.html#AccessPolicyLanguage_RequestContext) includes the [aws:PrincipalTag](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_condition-keys.html#condition-keys-principaltag) context key. You can use the aws:PrincipalTag key in the Condition element of your policies to allow or deny access based on those tags”_

### Description of changes

The CDK creates [4 IAM roles](https://docs.aws.amazon.com/cdk/v2/guide/bootstrapping-env.html#bootstrapping-env-roles) during bootstrap. It then assumes these roles at various phases of the deployment.

- [DeploymentActionRole](https://github.com/aws/aws-cdk/blob/v2.154.1/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml#L429): Assumed when invoking CloudFormation operations such as _Deploy_ and _DescribeStackEvents_.
- [FilePublishingRole](https://github.com/aws/aws-cdk/blob/v2.154.1/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml#L275): Assumed when file assets are uploaded to the bootstrap bucket.
- [ImagePublishingRole](https://github.com/aws/aws-cdk/blob/v2.154.1/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml#L298): Assumed when docker images are published to the bootstrap ECR registry.
- [LookupRole](https://github.com/aws/aws-cdk/blob/v2.154.1/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml#L321): Assumed while performing context lookups.

Each of these roles should be assumable with their own specific session tags, as they server different purposes.

> Note: The [CloudFormationExecutionRole](https://github.com/aws/aws-cdk/blob/v2.154.1/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml#L536) is also created during bootstrap, but the CLI never assumes it, therefore it doesn't need session tags support.

Session tags for each role will be configurable via synthesizer properties (similarly to how `externalId` is [exposed](#15604)) both for the `DefaultStackSynthesizer`, and for a custom synthesizer extending the `StackSynthesizer` class. The new properties will propagate down and will eventually be written to the cloud assembly.

#### `+ manifest.json`

```json
{
  "version": "36.0.0",
  "artifacts": {
    "MyStack.assets": {
      "type": "cdk:asset-manifest",
      "properties": {
        "file": "SeshTagsManifestStack.assets.json",
        "requiresBootstrapStackVersion": 6,
        "bootstrapStackVersionSsmParameter": "/cdk-bootstrap/hnb659fds/version"
      }
    },
    "MyStack": {
      "type": "aws:cloudformation:stack",
      "environment": "aws://unknown-account/unknown-region",
      "properties": {
        "assumeRoleArn": "arn:${AWS::Partition}:iam::${AWS::AccountId}:role/cdk-hnb659fds-deploy-role-${AWS::AccountId}-${AWS::Region}",
          "assumeRoleAdditionalOptions": {
            "Tags": < deployRoleSessionTags > 
          }
        "lookupRole": {
          "arn": "arn:${AWS::Partition}:iam::${AWS::AccountId}:role/cdk-hnb659fds-lookup-role-${AWS::AccountId}-${AWS::Region}",
          "requiresBootstrapStackVersion": 8,
          "bootstrapStackVersionSsmParameter": "/cdk-bootstrap/hnb659fds/version"
          "assumeRoleAdditionalOptions": {
            "Tags": < lookupRoleSessionTags > 
          }
        }
      },
```

#### `+ assets.json`

```json
{
  "version": "36.0.0",
  "files": {
    "9ebfd704f02f99b2711998e6435822b0dbed6e80dcac7e75f339fe894861ac20": {
      "source": {
        "path": "mystack.template.json",
        "packaging": "file"
      },
      "destinations": {
        "current_account-current_region": {
          "assumeRoleArn": "arn:${AWS::Partition}:iam::${AWS::AccountId}:role/cdk-hnb659fds-file-publishing-role-${AWS::AccountId}-${AWS::Region}"
          "assumeRoleAdditionalOptions": {
             "Tags": < fileAssetPublishingRoleSessionTags >
           }
        }
      }
    }
  },
  "dockerImages": {
    "dockerHash": {
      "source": {
        "directory": "."
      },
      "destinations": {
        "current_account-current_region": {
          "assumeRoleArn": "arn:${AWS::Partition}:iam::${AWS::AccountId}:role/cdk-hnb659fds-image-publishing-role-${AWS::AccountId}-${AWS::Region}"
          "assumeRoleAdditionalOptions": {
            "Tags": < imageAssetPublishingRoleSessionTags >
          }
        }
      }
    }
  }
}
```

### Description of how you validated changes

- CLI integration tests.
- CLI and framework unit tests.

### Checklist
- [X] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Allow passing [all STS options](https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRole.html#API_AssumeRole_RequestParameters) to assume role configuration for various CDK roles. 

> The following PR description focuses on Session Tags because it was originally the only option we wanted to add support to. After some thought, we decided to allow all available STS options via a transparent pass-through.

### Prerequisites

- cdklabs/cloud-assembly-schema#33
- cdklabs/cdk-assets#40

### Issue # (if applicable)

Closes aws/aws-cdk#26157 
Fixes aws/aws-cdk#22535

### Reason for this change

Enabling [ABAC](https://docs.aws.amazon.com/IAM/latest/UserGuide/introduction_attribute-based-access-control.html) via STS session tags. From the [AWS docs](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_session-tags.html):


> _“Session Tags are key-value pair attributes that you pass when you assume an IAM role or federate a user in AWS STS. You do this by making an AWS CLI or AWS API request through AWS STS or through your identity provider (IdP). When you use AWS STS to request temporary security credentials, you generate a session. Sessions expire and have [credentials](https://docs.aws.amazon.com/STS/latest/APIReference/API_Credentials.html), such as an access key pair and a session token. When you use the session credentials to make a subsequent request, the [request context](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements_condition.html#AccessPolicyLanguage_RequestContext) includes the [aws:PrincipalTag](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_condition-keys.html#condition-keys-principaltag) context key. You can use the aws:PrincipalTag key in the Condition element of your policies to allow or deny access based on those tags”_

### Description of changes

The CDK creates [4 IAM roles](https://docs.aws.amazon.com/cdk/v2/guide/bootstrapping-env.html#bootstrapping-env-roles) during bootstrap. It then assumes these roles at various phases of the deployment.

- [DeploymentActionRole](https://github.com/aws/aws-cdk/blob/v2.154.1/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml#L429): Assumed when invoking CloudFormation operations such as _Deploy_ and _DescribeStackEvents_.
- [FilePublishingRole](https://github.com/aws/aws-cdk/blob/v2.154.1/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml#L275): Assumed when file assets are uploaded to the bootstrap bucket.
- [ImagePublishingRole](https://github.com/aws/aws-cdk/blob/v2.154.1/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml#L298): Assumed when docker images are published to the bootstrap ECR registry.
- [LookupRole](https://github.com/aws/aws-cdk/blob/v2.154.1/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml#L321): Assumed while performing context lookups.

Each of these roles should be assumable with their own specific session tags, as they server different purposes.

> Note: The [CloudFormationExecutionRole](https://github.com/aws/aws-cdk/blob/v2.154.1/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml#L536) is also created during bootstrap, but the CLI never assumes it, therefore it doesn't need session tags support.

Session tags for each role will be configurable via synthesizer properties (similarly to how `externalId` is [exposed](aws/aws-cdk#15604)) both for the `DefaultStackSynthesizer`, and for a custom synthesizer extending the `StackSynthesizer` class. The new properties will propagate down and will eventually be written to the cloud assembly.

#### `+ manifest.json`

```json
{
  "version": "36.0.0",
  "artifacts": {
    "MyStack.assets": {
      "type": "cdk:asset-manifest",
      "properties": {
        "file": "SeshTagsManifestStack.assets.json",
        "requiresBootstrapStackVersion": 6,
        "bootstrapStackVersionSsmParameter": "/cdk-bootstrap/hnb659fds/version"
      }
    },
    "MyStack": {
      "type": "aws:cloudformation:stack",
      "environment": "aws://unknown-account/unknown-region",
      "properties": {
        "assumeRoleArn": "arn:${AWS::Partition}:iam::${AWS::AccountId}:role/cdk-hnb659fds-deploy-role-${AWS::AccountId}-${AWS::Region}",
          "assumeRoleAdditionalOptions": {
            "Tags": < deployRoleSessionTags > 
          }
        "lookupRole": {
          "arn": "arn:${AWS::Partition}:iam::${AWS::AccountId}:role/cdk-hnb659fds-lookup-role-${AWS::AccountId}-${AWS::Region}",
          "requiresBootstrapStackVersion": 8,
          "bootstrapStackVersionSsmParameter": "/cdk-bootstrap/hnb659fds/version"
          "assumeRoleAdditionalOptions": {
            "Tags": < lookupRoleSessionTags > 
          }
        }
      },
```

#### `+ assets.json`

```json
{
  "version": "36.0.0",
  "files": {
    "9ebfd704f02f99b2711998e6435822b0dbed6e80dcac7e75f339fe894861ac20": {
      "source": {
        "path": "mystack.template.json",
        "packaging": "file"
      },
      "destinations": {
        "current_account-current_region": {
          "assumeRoleArn": "arn:${AWS::Partition}:iam::${AWS::AccountId}:role/cdk-hnb659fds-file-publishing-role-${AWS::AccountId}-${AWS::Region}"
          "assumeRoleAdditionalOptions": {
             "Tags": < fileAssetPublishingRoleSessionTags >
           }
        }
      }
    }
  },
  "dockerImages": {
    "dockerHash": {
      "source": {
        "directory": "."
      },
      "destinations": {
        "current_account-current_region": {
          "assumeRoleArn": "arn:${AWS::Partition}:iam::${AWS::AccountId}:role/cdk-hnb659fds-image-publishing-role-${AWS::AccountId}-${AWS::Region}"
          "assumeRoleAdditionalOptions": {
            "Tags": < imageAssetPublishingRoleSessionTags >
          }
        }
      }
    }
  }
}
```

### Description of how you validated changes

- CLI integration tests.
- CLI and framework unit tests.

### Checklist
- [X] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

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*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*