Cluster Creation Flow implementation.

Session management improved in both cluster templates and clusters flows.

Change-Id: Id392bbcf92e072d0ab7eb53940ba2c81e3715688
Node Group Templates do not pass default configs.

Change-Id: Id0f5eb7ceeccd30cf1c844642e5e69d5f9ec523a
Merge "Cluster Creation Flow implementation."
Merge "Node Group Templates do not pass default configs."