chore: refactor internal modules

[marcelotduarte]

Also, use stdlib importlib.metadata for Python >= 3.10.2 (like pypa/build#693)

[codecov]

Codecov Report

Attention: Patch coverage is 76.92308% with 6 lines in your changes are missing coverage. Please review.

Project coverage is 80.25%. Comparing base (e0aa702) to head (14c5f08).

Files	Patch %	Lines
cx_Freeze/_importlib.py	77.77%	2 Missing ⚠️
cx_Freeze/_packaging.py	66.66%	2 Missing ⚠️
cx_Freeze/module.py	66.66%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2319      +/-   ##
==========================================
+ Coverage   80.23%   80.25%   +0.01%     
==========================================
  Files          25       27       +2     
  Lines        4018     4021       +3     
==========================================
+ Hits         3224     3227       +3     
  Misses        794      794              

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