DM-47972: Support entry points for loading external metadata translators

[timj]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 42.22222% with 26 lines in your changes missing coverage. Please review.

Project coverage is 87.32%. Comparing base (1e2c377) to head (ec985f2).
Report is 14 commits behind head on main.

✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...hon/astro_metadata_translator/cli/astrometadata.py	36.36%	17 Missing and 4 partials ⚠️
python/astro_metadata_translator/translator.py	50.00%	2 Missing and 1 partial ⚠️
python/astro_metadata_translator/bin/translate.py	0.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #80      +/-   ##
==========================================
- Coverage   87.97%   87.32%   -0.66%     
==========================================
  Files          37       37              
  Lines        3144     3187      +43     
  Branches      414      423       +9     
==========================================
+ Hits         2766     2783      +17     
- Misses        260      280      +20     
- Partials      118      124       +6     

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[JeremyMcCormick]

This looks good and makes the changes outlined here.

I verified using lsstsw tools that astrometadata --list-plugins shows the list of available translator plugins, and an update was also made by @timj to list the built-in translators as well.

I would suggest adding better test coverage for the plugin functionality in the future, possibly using a dummy/mock internal package. Or a CI repo could be created and depend on astro_metadata_translator plus several of the other repositories that implement plugins.