Add link to `Administration guide` on frontpage
Add link to `Administration guide` on frontpage

Change-Id: If4091b7882618a42381af923c7f6faa0460ea50f
Story: 2001654
Task: 27075

openstack/monasca-api,stackforge/monasca-api,stackforge/monasca-api,openstack/monasca-api,openstack/monasca-api,stackforge/monasca-api,stackforge/monasca-api