This creates a new ha-guide-draft directory to allow developing the
guide. Add infrastructure for:
* The draft guide is not translated currently.
* Build RST version (but not PDF yet) with each run.
* Publish guide as draft
* Update built index for it.
Also updates the ToC to reflect the proposed changes.
Implements: blueprint implement-ha-guide-todos
Change-Id: If6f65646e02ac3eac08c288fd727ab9851cf9569