The latter does not work well with Sphinx 2.0.
Switching brings us up to date with modern norms. The
changes made here are to get it working:
* Changing tox jobs to the modern style, with a separate
requirements.txt in the doc directory.
* Updating doc and releasenotes conf.py to use the new
theme and correctly point at storyboard for bugs
* Remove docs related requirements from test-requirements.txt
Change-Id: I9770f375b0fd7a6cacdd02e3d0381a28879f18b5
dbd50cbf97