setup.cfg instead of setup.py
Use `setup.cfg` instead of `setup.py` on the documentation and the `setup.py` generator.

- https://gist.github.com/juancarlospaco/b91d7736281e2090fce84ed399c68972

`.cfg` can be easy to generate/parse from Nim using `parsecfg` module, builtin on Python.
:slightly_smiling_face: 
