[python] Follow spec-0

[ivirshup]

Fixes #1177

This PR implements adoption SPEC-0 for support windows of dependencies.

I'm going to hold off on running formatting for all files until I'm done with the manual changes to make this readable.

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Blocked by tiledbsoma's pinning of pyarrow to v12 (current release is v16). It looks like it's difficult to install pyarrow~=12.0 on python 3.12 since there haven't been any wheel releases. See: single-cell-data/TileDB-SOMA#1926

[johnkerl]

Not positive it's entirely related but we had a hard fail on MacOS, beyond our control:
single-cell-data/TileDB-SOMA#1926 (comment)

[codecov]

Codecov Report

Attention: Patch coverage is 97.64706% with 2 lines in your changes missing coverage. Please review.

Project coverage is 91.21%. Comparing base (f775282) to head (dcf94bd).
Report is 1 commits behind head on main.

Files	Patch %	Lines
...us/src/cellxgene_census/experimental/_embedding.py	75.00%	1 Missing ⚠️
.../cellxgene_census/experimental/util/_eager_iter.py	75.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1189      +/-   ##
==========================================
+ Coverage   91.19%   91.21%   +0.02%     
==========================================
  Files          77       79       +2     
  Lines        5971     6146     +175     
==========================================
+ Hits         5445     5606     +161     
- Misses        526      540      +14     

Flag	Coverage Δ
unittests	91.21% <97.64%> (+0.02%)	⬆️

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[ivirshup]

I've gone ahead and made a few changes here.

Right now I've followed spec-0, but since we can't do 3.12 while tiledbsoma pins it I've just left off support there.

My last commit is just letting the formatter run + a couple manual fixes. I can revert it if other changes are needed.

[ivirshup]

This is ready for review. I think the main question is whether we want to drop support for python 3.8 and 3.9 if we can't support 3.12 while tiledbsoma pins it.

[github-actions]

This PR has not seen any activity in the past 4 weeks; if no one comments or reviews it in the next 3 days, this PR will be closed.

[ivirshup]

no