This repo is now testing only with Python 3, so let's make
a few cleanups:
- Remove python 2.7 stanza from setup.py
- Add requires on python >= 3.6 to setup.cfg so that pypi and pip
know about the requirement
- Remove obsolete sections from setup.cfg
- Update classifiers
- Update requirements, no need for python_version anymore
- Cleanup doc/source/conf.py to remove now obsolete content.
- Use newer openstackdocstheme and Sphinx versions
- Remove install_command from tox.ini, the default is fine
- Remove hacking from doc/requirements, we don't need to autodoc it.
- Remove Babel, this repo does not use it.
Change-Id: I8ad7b5e6ef11ea51c587ff58bfc54aee4fcda9da
1accaf2d8a