[Feature]: Collection-level Metadata for better execution-environment handling

[nwerker]

Please add and maintain the python requirements (modules: mitogen) of the collection in its Collection-level Metadata so that people can more easily use the collection in execution-environments when using it with or awx or ansible automation platform.

The Collection-level Metadata makes it more easy to include the collection in execution-environments, since the python dependencies will be automatically installed, when building the execution-environment.

Furthermore you could track the dependencies in context of a release.

If you need further information about the Collection-level Metadata here is some Documentation from the ansible-builder Project Documentation.

I'll provide a PR, in your case it's quiet easy since a requirements.txt will be sufficient!