Move admin-guide-cloud to docs.o.o/admin-guide-cloud/content

This changes the location in combination with
https://review.openstack.org/45936:

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: I78990083edc2a5c9da965889272f953550578f63
Merge "Move admin-guide-cloud to docs.o.o/admin-guide-cloud/content"