Decide a consistent URL for Python sources

[androidnisse]

There isn’t currently a standard for PyPI source URLs in Solus package builds. AerynOS uses URLs in this format: https://files.pythonhosted.org/packages/source/p/python-dateutil/python-dateutil-2.8.2.tar.gz

What is the preferred approach for Solus?

If this format is accepted, I’ve prepared a modified version of new-package.sh that automatically sanitizes the source URL to match it. I can also update the Packaging Changes and package.yml documentation accordingly.

Aeryn issue: https://github.com/AerynOS/recipes/issues/11