Make index.rst usable

* Update to reflect new directory structure
* Drop maxdepth to 1, to make the page smaller, otherwise the index will
  include links to each section of each blueprint. And since each
  section will have the same name across bluepints this is useless.

Change-Id: I2a5d94ae26002a884033d27881394a795592fe3f
Merge "Make index.rst usable"