In order to wrangle together a top level TOC that makes sense, stop
including everything in the TOC (ideally we could convince sphinx to
not warn on that).
This creates a Contributor Documentation landing page with deep links
to all the relevant documents. It removes all those links from the
front page, and the TOC. They can be found by deep links or search,
and it is a less confusing initial experience for folks.
Part of bp: doc-migration
Change-Id: If5e7940ddd0ae3316f7475742c02abfe3df28ac4
Sean Dague
a5acc83c21