Expansion of glossary list

Modify format; additional terms plus more content for each. Added Ceilometer, Red Hat,
notes from RN, Murano Quantum to Neutron, etc.
Added link to OVS docs to NIC article and OVS article
Added link to custom attributes info from Puppet article
Links to more Pacemaker info

Change-Id: Ida10bb53ec3978f0b07f5a1b4323638a4f5d1748