Refactored the wheel convert command to not require setuptools

[agronholm]

This also aims to improve the correctness of the egg and bdist_wininst conversions.

Fixes #510.

[codecov]

Codecov Report

Attention: Patch coverage is 96.02273% with 7 lines in your changes missing coverage. Please review.

Project coverage is 77.96%. Comparing base (e43464d) to head (5b4a98c).
Report is 8 commits behind head on main.

Files with missing lines	Patch %	Lines
src/wheel/cli/convert.py	96.02%	7 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #640      +/-   ##
==========================================
+ Coverage   71.18%   77.96%   +6.78%     
==========================================
  Files          14       14              
  Lines        1093     1121      +28     
==========================================
+ Hits          778      874      +96     
+ Misses        315      247      -68     

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[agronholm]

Gotta say, I spent way too much time on this feature that probably no one will use anymore...

[henryiii]

I don’t have a use for the command at the moment, but code looks reasonable.

[agronholm]

Thanks for the review!