CubeCL first iteration

[louisfd]

Part of #1665

Since the goal of CubeCL is to rewrite all our JIT kernels with a readable rusty syntax, I started by supporting all the basic syntax to parse it into to the JIT intermediate representation, and figured out an enjoyable type system for element types, with support for easy casting. To look at examples, navigate to crates/burn-cube/tests where kernels marked with #[cube] are tested against their gpu! macro counterparts.

Next steps:

• rename gpu macro to cube_inline (trivial, but didn't want to make this PR harder to read)
• support vectorization better
• migrate jit codegen stuff to cube

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 78.13688% with 460 lines in your changes are missing coverage. Please review.

Project coverage is 86.41%. Comparing base (1073752) to head (2bf7db9). Report is 6 commits behind head on main.

Files	Patch %	Lines
crates/burn-cube/tests/cast_elem.rs	58.16%	64 Missing :warning:
crates/burn-cube/src/operation/binary.rs	49.41%	43 Missing :warning:
crates/burn-cube/tests/function_call.rs	68.60%	27 Missing :warning:
crates/burn-cube/tests/trait.rs	81.61%	25 Missing :warning:
crates/burn-cube-macros/src/analysis.rs	85.71%	24 Missing :warning:
crates/burn-cube-macros/src/codegen/function.rs	65.67%	23 Missing :warning:
crates/burn-cube/src/element/conversion.rs	0.00%	22 Missing :warning:
crates/burn-cube/src/element/bool.rs	25.00%	18 Missing :warning:
crates/burn-cube/src/element/uint.rs	40.00%	18 Missing :warning:
crates/burn-cube/src/operation/cmp.rs	56.75%	16 Missing :warning:
... and 22 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1756      +/-   ##
==========================================
- Coverage   86.61%   86.41%   -0.21%     
==========================================
  Files         700      734      +34     
  Lines       83423    85575    +2152     
==========================================
+ Hits        72258    73947    +1689     
- Misses      11165    11628     +463     

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