Implement indexing operations in PyTorch

[HarshvirSandhu]

Implement indexing ops in pytorch

• [x] Subtensor
• [ ] IncSubtensor
• [x] AdvancedSubtensor[1]
• [ ] AdvancedIncSubtensor[1]

Description

Related Issue

• [x] Related to #821

Checklist

• [x] Checked that the pre-commit linting/style checks pass
• [x] Included tests that prove the fix is effective or that the new feature works

Type of change

• [x] New feature / enhancement

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 85.41667% with 14 lines in your changes missing coverage. Please review.

Project coverage is 81.74%. Comparing base (1a1c62b) to head (b38a01c). Report is 122 commits behind head on main.

Files with missing lines	Patch %	Lines
pytensor/link/pytorch/dispatch/subtensor.py	84.61%	9 Missing and 3 partials :warning:
pytensor/link/pytorch/dispatch/basic.py	87.50%	2 Missing :warning:

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #910   +/-   ##
=======================================
  Coverage   81.73%   81.74%           
=======================================
  Files         182      183    +1     
  Lines       47633    47724   +91     
  Branches    11604    11616   +12     
=======================================
+ Hits        38934    39011   +77     
- Misses       6509     6520   +11     
- Partials     2190     2193    +3     

Files with missing lines	Coverage Δ
pytensor/compile/mode.py	84.54% <ø> (ø)
pytensor/link/pytorch/dispatch/__init__.py	100.00% <100.00%> (ø)
pytensor/link/pytorch/dispatch/basic.py	93.33% <87.50%> (-1.54%)	:arrow_down:
pytensor/link/pytorch/dispatch/subtensor.py	84.61% <84.61%> (ø)

[ricardoV94]

@HarshvirSandhu I pushed some simplification and also needed special logic for repeated indices in IncSubtensor. Feel free to review and see if you spot any issues. Note that I squashed the commits and force-pushed, so you'll have to retrieve the remote branch before you can do any changes