[llvm] [mlir] [mlir python] Add nanobind support for standalone dialects. (PR #117922)

[Stella Laurenzo via llvm-commits]

stellaraccident wrote:

If that is a hard requirement, we will probably need to exclude the python packages from distribution in OS packages (they were never scoped for this anyway) or move them out of tree. The python ecosystem is simply moving too fast to gate on this. We cannot stay in sync with python.org development without being able to use bleeding edge deps in the bindings.

We could also vendor them into the monorepo if there was a strong push from the OS packaging side to distribute these demo bindings. I can't overstate how inconsequential this decision should be from a packaging standpoint.

I'll note that there is an RFC for this, which is a better place to have the discussion (I'm not sure many are monitoring this merged PR): 

https://discourse.llvm.org/t/nanobind-for-mlir-python-bindings/83511

https://github.com/llvm/llvm-project/pull/117922