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

[Loïc Jaquemet via cfe-commits]

trolldbois wrote:

> > Also I barely know anything about how to package this stuff correctly, and what the consequences would be if we get it wrong.
> 
> Also regarding @Endilll. Nothing can go wrong really. This is still not connected to the CD and you would need permission from [`clang` pypi project](https://pypi.org/project/clang/) for which @nightlark has an issue about [trolldbois/python-clang#21](https://github.com/trolldbois/python-clang/issues/21). The current state would be helpful to integrate early on, to allow people to experiment and integrate their CI, while any remaining nitpicks would be resolved when working on repairing the python CD (see #123937 and https://github.com/llvm/llvm-project/actions/runs/13661982395).

Happy to integrate with the pypi releases, trusted publishing whenever you are ready.

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