This patch refactors the monasca-agent role by bringing consistency
with the other openstack-ansible roles. Main changes include:
- Plugins are automatically configured based on the openstack-ansible
configuration;
- Added tests;
- Added documentation.
The extras directory contains changes necessary to openstack-
ansible to setup monasca-agent.
Change-Id: I3678af93ef460e5c32751e08201e68cef216787d