Improve preparation and verification of source tarballs

[potiuk]

After testing with Alpha 2 ATR (Apache Trusted Releases) of airflow-ctl it turned out that our source tarballs were not perfectly according to what ATR expected.

• The -source tarballs did not have internal directory with -source sufffix

• The verification of those tarballs with RAT 0.17.0 was done using the .rat-excludes from airflow sources - not from the package itself

• For provider releases, we verified way more than we should with licence checks (we should really only verify the sources, not the whl or .sdist files.

The commands to generate the tarballs also had some inconsistencies and repetitions:

• Literals were sprinkled across the code base

• In some cases we would produce tarballs when generating distributions which was not exactly matching the general "prepare-airflow-tarball" behaviour regarding tags and versions.

• It was difficult to test tarball preparation locally before tags were created for the version to test

• Tarballs should never be produced with rc suffix. We always produce tarballs with the "final version" of the component because tarballs are not published in PyPI and can be promoted to the final version always.

This PR simplifies the scripts and makes it more consistent:

• tarballs are only created with prepare-tarball command
• Literals are removed and replaced wiuth TarballType enum (DRY)
• behaviour of tarball generation is more predictable now and consistent:
  • you specify tarball type
  • if you do not specify version, tag is HEAD, and version is automatically retrieved based of the version of tarball type
  • if you specify version - prefix (airflow-ctl/, airflow-task-sdk/, providers/) is added to the version to derive a tag and that version is used as tarball version (prefixed with type)
  • tarball-type-version-source is used as top-level folder where the sources are placed
• verification of licences is now consistent, simplified and produces better results - showing counts of checked files and exclusions used - not only files that have unknown or unapproved licences. You can actually see that RAT did it's job.

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[bugraoz93]

Thanks Jarek!

[github-actions]

Backport failed to create: v3-1-test. View the failure log Run details

Status	Branch	Result
❌	v3-1-test

You can attempt to backport this manually by running:

cherry_picker c3669c0 v3-1-test

This should apply the commit to the v3-1-test branch and leave the commit in conflict state marking
the files that need manual conflict resolution.

After you have resolved the conflicts, you can continue the backport process by running:

cherry_picker --continue

[potiuk]

Manual backport #57906