Remove import exception in Python3.12

[paaguti]

Python 3.12 doesn't support png_resources anymore. We need to circumvent this by using import lib_metadata instead.

[Avasam]

Python 3.12 doesn't support pkg_resources anymore

Python 3.12 doesn't ship distutils in the stdlib anymore. setuptools still has distutils and pkg_resources.
On Python 3.8+ importlib.metadata should also be preferred over the backport importlib_metadata. I created a similar PR (#25) with a slightly different approach as I also want to stop relying on setuptools at runtime. Up to the maintainers which approach they prefer.