moved most of setup to pyproject

[shimwell]

Description

This PR changes from a setup.py to a pyproject.toml

• It requires python 3.8 or above, this allows the version to be found with importlib.metadata
• changes the scripts names, this is compatible with python file naming requirments
• doesn't move the cythonize part from the setup.py but this could in theory be done like this

Checklist

• I have performed a self-review of my own code
• I have followed the style guidelines for Python source files (if applicable)

[MicahGale]

I think this is a good start. However this still depends on a setup.py workflow instead of something like python -m build. To ultimately future proof this setup.py should be removed, but I'm not sure if that's possible yet. Looking into this I wasn't able to find an easy way to get cython and build to all cooperate. Though I did come across scikit-build which seemed promising.

[MicahGale]

I would recommend using dynamic metadata instead to keep this more consistent with what people expect: dynamic metadata.

[MicahGale]

Also relevant blog post on setup.py deprecation: https://blog.ganssle.io/articles/2021/10/setup-py-deprecated.html