[Distroless] Reorganize and refactor Distroless build and test details

[damondouglas]

This PR addresses #32817 and addresses #32818 reorganizing and refactoring the mechanism to build and test distroless variants.

Please ignore any of the GitHub workflows that include 'Distroless' in its name as these are expected to fail, such as beam_PostCommit_Java_ValidatesDistrolessContainer_Dataflow.

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 57.42%. Comparing base (4a32482) to head (00319f8).
Report is 4 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##             master   #33494   +/-   ##
=========================================
  Coverage     57.42%   57.42%           
  Complexity     1475     1475           
=========================================
  Files           980      980           
  Lines        155081   155081           
  Branches       1076     1076           
=========================================
  Hits          89063    89063           
  Misses        63819    63819           
  Partials       2199     2199           

Flag	Coverage Δ
python	81.23% <ø> (ø)

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[damccorm]

Thank you - I think this is a good approach. I had one piece of (very minor) feedback, otherwise this LGTM

[damccorm]

Could you add a comment here (and in the sdks/python/container/build.gradle file same spot saying that these need to be kept in sync?

[Abacn]

thank you!