Document config drive on vmware

Add documentation which lists which hypervisors implement config
drive at the moment.

Resolves bug 1212234.

Change-Id: Ifd59309c689369a16f448233daec443fcb476c6e
Move admin-guide-cloud to docs.o.o/admin-guide-cloud/content

This patch removes admin from the URL.
This needs a change in the jenkins files as well to remove cloud-admin.
Current URL is : docs.o.o/cloud-admin/admin-guide-cloud/admin/content
New URL will be: docs.o.o/admin-guide-cloud/content

Change-Id: I4b5412996917836ecc8326d7c75e69db7ae1764d
Merge "Move admin-guide-cloud to docs.o.o/admin-guide-cloud/content"
Merge "Document config drive on vmware"