Polish 'Savanna Deployment' page

That incorporates feedback given by Meg McRoberts in
https://review.openstack.org/#/c/71299/4/pages/reference-architecture/0090-savanna.rst

I didn't have time to make this change back then, but I think it would be
nice to have it in 5.0.

Change-Id: I027eab13dc5367fbc74b14444a4da1fdb11f52e4
delete unused files from install-guide

Change-Id: I5cc2721433a52086215286c47b9bc1240362b8e2
split openstack-patch source into modular files

Change-Id: I998ff7a9eaa4a30ea5ec68a115a3c58f6c25957a
baseline express doc files

Change-Id: If610714a7f846a86ba7e8b1b8941bf6fc78ebb39
Merge "split openstack-patch source into modular files"