Trigger the Docs workflow on version tags (v*) and add a deploy job
that publishes the built Sphinx HTML to the gh-pages branch using
peaceiris/actions-gh-pages. PRs and branch pushes still build (and
now upload an artifact) but do not deploy.
- Full cleanup of all the docs
- General sphinx housekeeping
- Updated all the old/bad links
- More reliable tests
- Updated Changelog
- Removed dead/deprecated code
- Added documentation generation test