Add Nox sessions for running pre-commit and checking MANIFEST.in

[namurphy]

• I added a lint session for Nox as a shortcut to run pre-commit run --all-files. This is mostly syntactic sugar, but does remove the need to install pre-commit manually.
• I added the manifest session for Nox to run check-manifest, which checks that all appropriate files are included in MANIFEST.in.
• I added a configuration for check-manifest in pyproject.toml
• I updated MANIFEST.in accordingly

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.25%. Comparing base (9340245) to head (f21d01d).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2695   +/-   ##
=======================================
  Coverage   95.25%   95.25%           
=======================================
  Files         104      104           
  Lines        9435     9435           
  Branches     2159     2159           
=======================================
  Hits         8987     8987           
  Misses        272      272           
  Partials      176      176           

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[namurphy]

This makes it so that MANIFEST.in gets checked for every PR, but we can switch it to a weekly test after #2694 is merged.

[pheuer]

I only about 50% understand what is going on with this tox->nox transition, but insofar as this PR defines a few new sessions for checking the manifest and running pre-commit, I think I understand and it looks good :)

[namurphy]

Awesome, thank you for the review!