Unified publishing to the readthedocs with other Airship projects.
Updated code convention for new documentation location.
Change-Id: If3b634bf04ed36b3f88831f0a276809ce6539b42
* Rename docs => doc for OpenStack convention compliance
* Add tox.ini job for docs building (no setup.py required)
* Add Makefile with docs entrypoint
* Add a link to the airship-specs subproject.
Change-Id: I835633405b3dac671aa123eb4ee04645f390c352