WIP: feat: add support for uploading Conan Python package to a PyPI index

[martinm82]

We have a Python Conan Package which contains some functionality that is re-used in conan recipies (python_requires) but could as well be re-used in other pure Python modules (pip).

This PR is introducing a new hook (post_upload) that generates a simple setup.py file, creates a source distribution and uploads it to a PyPI index via twine.

Not sure this is something you would be interested in.

In general I am as well interested in getting your feedback.

[lasote]

Hi! I don't really understand the use case, but at first sight, a post upload hook that publishes to pypi sounds a bit weird. How does it know which packages have to be uploaded to pypi? How are you using this generator?