Deprecate PSA and replace with PathSimAnalysis mdakit

[IAlibay]

Towards #4308

Changes made in this Pull Request:

• Remove local PSA code in favour of importing directly from PathSimAnalysis

TODO:

• Remove tests
• Add raising of warning
• Decide what to do with docs
• Fix py3.12 deployment upstream

PR Checklist

• Tests?
• Docs?
• CHANGELOG updated?
• Issue raised/referenced?

Developers certificate of origin

• I certify that this contribution is covered by the LGPLv2.1+ license as defined in our LICENSE and adheres to the Developer Certificate of Origin.

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📚 Documentation preview 📚: https://mdanalysis--4403.org.readthedocs.build/en/4403/

[github-actions]

Linter Bot Results:

Hi @IAlibay! Thanks for making this PR. We linted your code and found the following:

Some issues were found with the formatting of your code.

Code Location	Outcome
main package	⚠️ Possible failure
testsuite	⚠️ Possible failure

Please have a look at the darker-main-code and darker-test-code steps here for more details: https://github.com/MDAnalysis/mdanalysis/actions/runs/7438905975/job/20238164847

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Please note: The black linter is purely informational, you can safely ignore these outcomes if there are no flake8 failures!

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (97b5a61) 93.41% compared to head (0ab9fdc) 93.35%.
Report is 3 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #4403      +/-   ##
===========================================
- Coverage    93.41%   93.35%   -0.06%     
===========================================
  Files          171      185      +14     
  Lines        22511    23117     +606     
  Branches      4129     4040      -89     
===========================================
+ Hits         21028    21582     +554     
- Misses         963     1039      +76     
+ Partials       520      496      -24     

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[IAlibay]

Discussion points:

1. Tests: I opted to just remove all the tests except from the ones checking for the module import warning. The idea here is that we then don't have to duplicate efforts trying to fix two things at the same time. However, it does mean that we're running CI less often / we're less likely to pick up things like NumPy 2.0 future issues.
2. Docs: Again here I opted to remove the docs and just point to pathsimanalysis, so that we can keep everything synced up. However it means that the docs don't really do much anymore.

[IAlibay]

Ok this is good to go - discussion from last week's call was that we would remove docs & tests and just intersphinx to the kits.

[IAlibay]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[orbeckst]

I agree with the decisions & looks fine to me.

Docs show the deprecation and link to PSA kit ✅

[IAlibay]

Thanks @orbeckst !