Introduce a SPEC file that can be used to create an RPM from a Python
source distribution. Some notable features of this SPEC file follow:
1. We can use this SPEC file to create both regular RPM packages and
ones targeted for Qubes.
2. It has a post installation script that removes stale .egg-info
directories, which previously caused issues to our users.
3. It automatically creates a changelog from our Git logs, which differs
from the actual CHANGELOG.md.
4. It folloes the latest Fedora guidelines (as of writing this) for
packaging Python projects.
Fixes#514
