Vectors working on GPU

[ygorpontelo]

Basic idea is for the vectors to also support GPU.

The current implementation allows for SIMD which is already pretty good. Given that the most important operations on any ML algorithms are on arrays, this new feature would be a great selling point for the whole area. This seems to me like a natural fit on the functionality of vectors and it would benefit various other applications besides ML.

LLVM seems to be expanding support for targeting GPUs: https://mlir.llvm.org/docs/Dialects/GPU/. Other projects like Triton use llvm as well. We would not need the whole set of features however, since we are not taking arbitrary code and compiling to GPU, only the vector type would be able to access this functionality.