Port Python bindings to nanobind

[MikePopoloski]

Should be faster compile times and runtimes, but need to check if we're limited by the lack of multiple inheritance.

[MikePopoloski]

I took a look at this; it's too large a lift right now given that nanobind doesn't support our style of multiple inheritance. We don't actually need to expose the multiple inheritance to Python so I think it could be made to work but would need a few small tweaks to nanobind and it's not worth the effort.