Overhaul PythonAPI, switch to scikit-build-core.

[MarcelPiNacy]

This switches the PythonAPI build from setuptools to scikit-build-core.

Where has this been tested?

• Platform(s): Windows 10
• Python version(s): 3.8
• Unreal Engine version(s): CARLA-UE5.3

[update-docs[bot]]

Thanks for opening this pull request! The maintainers of this repository would appreciate it if you would update our CHANGELOG.md based on your changes.