Provide binary wheels for pypi for MacOS M1 (and others)

[SimonCW]

This is to collect ToDo's and Discussions around enabling MacOS M1 support. Any help welcome.

There might be a quick fix for achieving this but since I'm not well-versed in the whole Cython build stuff I'll need to clean up some other issues that are popping up first:

• [ ] Update deprecated functions in setup.py
• [ ] Simplify CFLAGS (take provided CFLAGS from conda-forge builds as model)
• [ ] Create build script for MacOS M1 in github action
• [ ] Publish new version to pypi

Conda-forge:

• [x] Update conda-forge feedstock https://github.com/conda-forge/lightfm-feedstock

[SimonCW]

Fyi: You can now install lightfm on macos m1 from conda-forge! conda install -c conda-forge lightfm