MNT: Configure project for isolated builds

[effigies]

Right now, installing a tool that depends on transforms3d results in:

  DEPRECATION: transforms3d is being installed using the legacy 'setup.py install' method, because it does not have a 'pyproject.toml' and the 'wheel' package is not installed. pip 23.1 will enforce this behaviour change. A possible replacement is to enable the '--use-pep517' option. Discussion can be found at https://github.com/pypa/pip/issues/8559
  Running setup.py install for transforms3d: started
  Running setup.py install for transforms3d: finished with status 'done'

This PR moves to a pyproject.toml configuration, replacing setup.cfg, versioneer.py, MANIFEST.in and most of setup.py.

[matthew-brett]

Thanks Chris.

[codecov]

Codecov Report

Merging #59 (8b6ffe0) into main (76213cc) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main      #59   +/-   ##
=======================================
  Coverage   97.00%   97.00%           
=======================================
  Files          27       27           
  Lines        1471     1471           
  Branches      140      140           
=======================================
  Hits         1427     1427           
  Misses         31       31           
  Partials       13       13           

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