[clang] [llvm] [libclang/python] Enable packaging libclang bindings (PR #125806)

[Cristian Le via llvm-commits]

https://github.com/LecrisUT approved this pull request.

My review is that it looks good to go for the scope that it serves. Follow up changes I would recommend is to align the CI and `pyproject.toml` across the other python projects, but it seems that it has been broken for a while, so it's a bigger issue to address.

https://github.com/llvm/llvm-project/pull/125806