Generate Python type stubs using nanobind (v2)

[garth-wells]

Nanobind can now auto-generate a type stubs for the wrapper code.

This has been used with Basix (FEniCS/basix#829).

[Jocho-Smith]

This issue can be closed right?

[schnellerhase]

Hi @Jocho-Smith, no this issue is still accurate. Changes in #4096 have been reverted in #4100. In particular the current CI setup did not check the generated stubs adequately. #4135 addresses this, together with #4131 we can then eventually roll this out (again) in #4101.