Use nanobind instead of pybind

[deependujha]

nanobind is used by some of the prominent open-source repos from big-techs, like, SPDL (Scalable and Performant Data Loading) from Meta use nanobind.

Also, according to nanobind's website:

• it shows up to ~4× faster compile time
• ~5× smaller binaries,
• ~10× lower runtime overheads compared to pybind11.
• nanobind also outperforms Cython in important metrics (3-12× binary size reduction, 1.6-4× compilation time reduction, similar runtime performance)