Cleanup numba dispatches

[ricardoV94]

Spinoff some cleanup from #1637

There was a lot of cruft in dispatch/basic.py, not to be confused with dispatch/tensor_basic.py, including a duplicated dispatch of Solve?

This PR moves things to better files, removes unused functions, and makes other obsolete.

It removes the helper to_scalar, that made numba dispatchers more permissive than they need to be?
This might have been originally here due to numba/numba#10266 but the work-around should happen at the relevant Elemwise op level, not in functions that accept 0d arrays. Otherwise we end up chasing this everywhere (and probably missing it in some places)

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📚 Documentation preview 📚: https://pytensor--1648.org.readthedocs.build/en/1648/

[codecov]

Codecov Report

❌ Patch coverage is 90.70796% with 21 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.63%. Comparing base (602eb04) to head (c594eb4).

Files with missing lines	Patch %	Lines
pytensor/link/numba/dispatch/basic.py	77.77%	7 Missing and 3 partials ⚠️
pytensor/link/numba/dispatch/subtensor.py	82.92%	5 Missing and 2 partials ⚠️
pytensor/link/numba/dispatch/elemwise.py	90.47%	3 Missing and 1 partial ⚠️

❌ Your patch check has failed because the patch coverage (90.70%) is below the target coverage (100.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1648      +/-   ##
==========================================
+ Coverage   81.58%   81.63%   +0.05%     
==========================================
  Files         240      242       +2     
  Lines       53593    53564      -29     
  Branches     9454     9451       -3     
==========================================
+ Hits        43722    43727       +5     
+ Misses       7395     7360      -35     
- Partials     2476     2477       +1     

Files with missing lines	Coverage Δ
pytensor/configdefaults.py	73.54% <ø> (-0.09%)	⬇️
pytensor/configparser.py	92.55% <ø> (-0.03%)	⬇️
pytensor/link/numba/dispatch/__init__.py	100.00% <100.00%> (ø)
pytensor/link/numba/dispatch/extra_ops.py	95.51% <100.00%> (+0.02%)	⬆️
pytensor/link/numba/dispatch/scalar.py	87.64% <100.00%> (-2.64%)	⬇️
pytensor/link/numba/dispatch/scan.py	96.02% <ø> (-0.03%)	⬇️
pytensor/link/numba/dispatch/shape.py	100.00% <100.00%> (ø)
pytensor/link/numba/dispatch/sort.py	100.00% <100.00%> (ø)
pytensor/link/numba/dispatch/tensor_basic.py	88.33% <100.00%> (+0.94%)	⬆️
pytensor/link/numba/dispatch/elemwise.py	94.28% <90.47%> (-0.54%)	⬇️
... and 2 more

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[Armavica]

Thanks, I will start reviewing this PR this weekend

[Armavica]

A few questions otherwise that looks good to me!

[Armavica]

I think there is a function call missing?

[ricardoV94]

that could mean we actually don't need (or are not testing) this functionality... Should show up in runtime slices

[ricardoV94]

I added a test, and actually fixed it a bit (last commit). This can all be removed after #541 is fixed, as we won't need to represent slices symbolically anymore