Convert pip-installed dev dependencies to Conda

[maresb]

The package sphinx-remove-toctrees was being installed via pip, so I created a Conda package for it, and now it can be installed via Conda. Also, polygamma is available through Conda. Thus I modified [windows-]environment-dev.yml so that no dependencies are pip installed.

What is this PR about?
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Checklist

• Explain important implementation details 👆
• Make sure that the pre-commit linting/style checks pass.
• Link relevant issues (preferably in nice commit messages)
• Are the changes covered by tests and docstrings?
• Fill out the short summary sections 👇

Major / Breaking Changes

• ...

Bugfixes / New features

• ...

Docs / Maintenance

• Refactor the installation of a few dependencies

[codecov]

Codecov Report

Merging #6060 (52ff529) into main (956cb09) will increase coverage by 1.58%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #6060      +/-   ##
==========================================
+ Coverage   87.97%   89.55%   +1.58%     
==========================================
  Files          72       72              
  Lines       12931    12931              
==========================================
+ Hits        11376    11581     +205     
+ Misses       1555     1350     -205     

Impacted Files	Coverage Δ
pymc/sampling_jax.py	97.15% <0.00%> (+97.15%)	⬆️