[Refactor] Create an Intermediate representation of compute shaders on the GPU

[nathanielsimard]

Decouple de data structures used for generating gpu shaders from the ones compiling the shaders to wgsl. I added 2 dialects: gpu and wgsl, more will come.

There are some places where the compiler is hardcoded, but it's going to be updated and removed in following PRs as we migrate all operations to the gpu dialect and support compiling to wgsl.

Todos

• Update the documentation

[louisfd]

Scanned it kinda fast but it's pretty awesome how ops are generic over the compiler