Remove Essex/Folsom cruft from Grizzly guides

partially fixes bug 1087484

With Grizzly a couple months away, the documentation team is working
on its documentation as a priority. As part of the release of new
documents, references to previous releases that are no longer useful
or relevent should be removed.

This change:
* removes reference to pre-essex legacy options on keystone import
* removes deleted simple scheduler from glossary
* clarifies XenAPI pools for current status
* removes note about Essex client mismatch in reset-stat
* removes references to Essex and Diablo from dodai-deploy docs
* removes an outdated (Essex) configuration file example
* updates several links to point to Grizzly versions
* removes outdated (Essex) ISO distribution information
* removes outdated (Diablo, Essex) vnc proxy information
* updates guide titles and versions where appropriate
* removes old notes about config syntax

Change-Id: I81fab078f17a003c12b7f86cb266892b89c79a94