Set up packaging metadata

[adigitoleo]

I have been reading about python packaging recently (for some personal projects and just out of interest) and I think I'm ready to attempt setting up packaging metadata for this project. The eventual goal is to enable publishing of the code to https://pypi.org/ which allows simple installation via pip install, setup.py install or simillar.

There are some things that still need more research, like how to specify ray OR charm4py as the parallelism dependency, but I'll push up a branch with what I have so far.

Cheers,
Leon

[adigitoleo]

It turns out that mutually exclusive dependencies are not currently supported in Python's setuptools. See pypa/packaging-problems/issues/432 and pypa/packaging-problems/issues/214 for reference. For now I will probably specify both ray and charm4py as optional dependencies. This means neither will be installed aoutomatically by pip, unless using the syntax pip install pydrex[ray] for example.