Add the role monasca-user to mini-mon

This is prep work for resolving the issue where the API
treats Agent role as restriction. This gives the mini-mon a role that
can be checked for monasca API access. The monasca-keystone role will
create this role if it doesn't exist

Change-Id: I8c36dbbda516aefc9600290932f315e9f4bdfc1f
Merge "Add the role monasca-user to mini-mon"