pyproject.toml, Hatch, and MIT license

[aazuspan]

This PR would:

1. Switch from setup.py to pyproject.toml, allowing for a cleaner project structure by combining a lot of tool configurations.
2. Switch build system from setuptools to hatch, removing developer dependencies on bumpversion and twine and moving all scripts from the makefile into pyproject.toml with isolated environments.
3. Switch to MIT license.

[codecov-commenter]

Codecov Report

Merging #64 (5a270ca) into main (6dc253d) will increase coverage by 3.77%.
The diff coverage is n/a.

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@@            Coverage Diff             @@
##             main      #64      +/-   ##
==========================================
+ Coverage   93.75%   97.52%   +3.77%     
==========================================
  Files          12       20       +8     
  Lines         512     1050     +538     
  Branches       53        0      -53     
==========================================
+ Hits          480     1024     +544     
- Misses         23       26       +3     
+ Partials        9        0       -9     

see 10 files with indirect coverage changes

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