Proposed changes

Create a single module that contains ids for Smartrest messages and static templates.

• user code is easier to read
• can easily jump to definition
• easier to see the dependency and find usages by grepping for the usage of the module

The next steps would be for thin-edge not to use these ids directly, but to provide a higher-level layer of abstraction for interacting with Cumulocity, much like go-c8y-cli.

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Improvement (general improvements like code refactoring that doesn't explicitly fix a bug or add any new functionality)
• Documentation Update (if none of the other choices apply)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Paste Link to the issue

Checklist

• I have read the CONTRIBUTING doc
• I have signed the CLA (in all commits with git commit -s)
• I ran cargo fmt as mentioned in CODING_GUIDELINES
• I used cargo clippy as mentioned in CODING_GUIDELINES
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments