Update README and setup.cfg, initial version of usage guide

* Set setup.cfg URL to the (future) documentation link
* Remove Python 3.3 and 3.4 support, leave only 3.5
* Update README with actual information
* Include README in index.rst as an introduction
* Very basic usage guide, mostly links to Tempest docs
* Switch links to HTTPS

Depends-On: If130b765604d606420a4877a548e82d311ef7b9b
Change-Id: Idacf84322773e40eaaa6346dc062291578876a1d
6 files changed