[Frontend] Refactor compiler

[erick-xanadu]

Context: Prepares changes for allowing easier debugging. The idea to improve debugging is to allow easy prototypes of new compilation pipelines which may circumvent some of the default behaviour. For example, instead of generating the MLIR module from python, load it from a string. Instead of generating LLVM-IR, load it from a file. These debugging changes are not yet implemented, but these will be implemented on top of this refactoring.

Description of the Change:

1. Passes are now classes. This allow developers/users looking to change flags to inherit from these passes and change the flags.
2. Passes are now passed as arguments to the compiler. Custom passes can just be passed to the compiler as an argument as long as they implement a run method which takes an input and the output of this method can be fed to the next pass.

Benefits: Treats the compiler as a library and allows prototyping alternative compilation flows.

[sc-36252]

[codecov]

Codecov Report

Merging #38 (c0a0d7c) into main (c9032f5) will increase coverage by 0.46%.
The diff coverage is 100.00%.

❗ Current head c0a0d7c differs from pull request most recent head f17b0a1. Consider uploading reports for the commit f17b0a1 to get more accurate results

@@            Coverage Diff             @@
##             main      #38      +/-   ##
==========================================
+ Coverage   98.24%   98.71%   +0.46%     
==========================================
  Files          34       34              
  Lines        5532     5531       -1     
  Branches      261      265       +4     
==========================================
+ Hits         5435     5460      +25     
+ Misses         55       40      -15     
+ Partials       42       31      -11     

Impacted Files	Coverage Δ
frontend/catalyst/compilation_pipelines.py	100.00% <100.00%> (+8.72%)	⬆️
frontend/catalyst/compiler.py	100.00% <100.00%> (+1.06%)	⬆️
frontend/catalyst/jax_tracer.py	90.71% <100.00%> (ø)
frontend/catalyst/utils/gen_mlir.py	100.00% <100.00%> (ø)

... and 9 files with indirect coverage changes

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[dime10]

Awesome work, really like the redesign of the compiler script into something more structured 💯

[maliasadi]

Thanks @erick-xanadu! I really like our brand new classified compiler 😄 Just re-reviewed my earlier review and there isn't much more to add. A few minor suggestions but it should be good to be merged from my side.

[dime10]

Looks great 💯