Bring up broker endpoints

If a Broker is running on the node, we need ensure the handler will
service its endpoints.
Add missing default config paths and help

They were missing for 'create-cluster' and 'join-cluster'.
Correct path of storage dir for 'create-cluster'
Create storage dir for 'join-cluster' if needed
Merge pull request #1212 from otoolep/add_raft_endpoints

Add Raft endpoints and fix cluster init bugs