This PS adds tooling and automation to automatically generate
Drydock's documentation into feature-rich HTML pages that can
be hosted.
To run the documentation job, simply execute:
tox -e docs
A future PS should add warning_is_error to 'build_sphinx' in
setup.py once the import warnings are addressed.
Change-Id: I91a3c585b2c27096e7fde12d180638d1ae4bdb81