aws-ec2: Export NatGatewayProvider

### Describe the feature

(originally posted as [a discussion](https://github.com/aws/aws-cdk/discussions/28154))

There are two implementations of [NatProvider](https://github.com/aws/aws-cdk/blob/c6471f2f603e2570e8781d6e1ae7d8252aec0f79/packages/aws-cdk-lib/aws-ec2/lib/nat.ts#L55-L100): [NatGatewayProvider](https://github.com/aws/aws-cdk/blob/c6471f2f603e2570e8781d6e1ae7d8252aec0f79/packages/aws-cdk-lib/aws-ec2/lib/nat.ts#L217-L261) and [NatInstanceProvider](https://github.com/aws/aws-cdk/blob/c6471f2f603e2570e8781d6e1ae7d8252aec0f79/packages/aws-cdk-lib/aws-ec2/lib/nat.ts#L266-L356).


Of the two, only NatInstanceProvider is exported. Both are usable through `aws_ec2.NatProvider.instance()` and `aws_ec2.NatProvider.gateway()` respectively, but since only NatInstanceProvider is exported [the docs](https://docs.aws.amazon.com/cdk/api/v2/docs/aws-cdk-lib.aws_ec2.NatProvider.html) indicate that `NatProvider` is only implemented by `NatInstanceProvider`.

I suggest that NatGatewayProvider also be exported, so that both providers are available through both interfaces and so the docs correctly reflect the two available implementations of `NatProvider`.

### Use Case

No real new functionality is exposed, except the ability to instantiate NatGatewayProvider directly instead of using the static method of NatProvider. The main advantage is the implied update to the docs.

### Proposed Solution

I think this is as simple as inserting an `export` at the start of L217 https://github.com/aws/aws-cdk/blob/c6471f2f603e2570e8781d6e1ae7d8252aec0f79/packages/aws-cdk-lib/aws-ec2/lib/nat.ts#L214-L261

### Other Information

_No response_

### Acknowledgements

- [X] I may be able to implement this feature request
- [ ] This feature might incur a breaking change

### CDK version used

2.115.0

### Environment details (OS name and version, etc.)

Windows 10

	/**
	* Provider for NAT Gateways
	*/
	class NatGatewayProvider extends NatProvider {
	private gateways: PrefSet<string> = new PrefSet<string>();

	constructor(private readonly props: NatGatewayProps = {}) {
	super();
	}

	public configureNat(options: ConfigureNatOptions) {
	if (
	this.props.eipAllocationIds != null
	&& !Token.isUnresolved(this.props.eipAllocationIds)
	&& this.props.eipAllocationIds.length < options.natSubnets.length
	) {
	throw new Error(`Not enough NAT gateway EIP allocation IDs (${this.props.eipAllocationIds.length} provided) for the requested subnet count (${options.natSubnets.length} needed).`);
	}

	// Create the NAT gateways
	let i = 0;
	for (const sub of options.natSubnets) {
	const eipAllocationId = this.props.eipAllocationIds ? pickN(i, this.props.eipAllocationIds) : undefined;
	const gateway = sub.addNatGateway(eipAllocationId);
	this.gateways.add(sub.availabilityZone, gateway.ref);
	i++;
	}

	// Add routes to them in the private subnets
	for (const sub of options.privateSubnets) {
	this.configureSubnet(sub);
	}
	}

	public configureSubnet(subnet: PrivateSubnet) {
	const az = subnet.availabilityZone;
	const gatewayId = this.gateways.pick(az);
	subnet.addRoute('DefaultRoute', {
	routerType: RouterType.NAT_GATEWAY,
	routerId: gatewayId,
	enablesInternetConnectivity: true,
	});
	}

	public get configuredGateways(): GatewayConfig[] {
	return this.gateways.values().map(x => ({ az: x[0], gatewayId: x[1] }));
	}
	}

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aws-ec2: Export NatGatewayProvider #28372

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aws-ec2: Export NatGatewayProvider #28372

Description

Describe the feature

Use Case

Proposed Solution

Other Information

Acknowledgements

CDK version used

Environment details (OS name and version, etc.)

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

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