WIP: add support for creating pyX.Y providers
Now all python packages that install to site-packages have the packages they provide tracked via the pyX.Y: provides.
Each directory under usr/lib/pythonX.Y/site-packages are converted into a pyX.Y provider.
1 directory is converted into a name usr/lib/python3.7/site-packages/foo -> py3.7:foo
1 file ending with .py converted to a name usr/lib/python3.7/site-packages/foo.py -> py3.7:foo