3eb809dd034cc93685f36a175f52ff7e49e03f23

There is currently no width restriction on documentation pages, which means long paragraphs take up the entire width of the browser window. On widescreen monitors this makes it uncomfortable to view the documentation. Fix the width to 900px, and make the content centered. Change-Id: Iffdd4a113997685da5669e1eb2d6d5666b846357
Description
RETIRED, Gerrit as used by OpenStack