[llvm] [mlir] [mlir python] Port in-tree dialects to nanobind. (PR #119924)

[Peter Hawkins via llvm-commits]

hawkinsp wrote:

Rebased this PR on top of main.

I might let https://github.com/llvm/llvm-project/pull/120473 sit for a day or two before merging this, but this PR should be good to go.

https://github.com/llvm/llvm-project/pull/119924