Agents to manage services provided by Openstack API

When deploying a high-availability stack within Openstack instances, some core resources need to be managed, such as block storage (cinder) or public IPs (floating ip). In order to achieve this goal with Openstack, new resource agents should be provided. For example: openstack-info (updates attributes openstack_az, openstack_flavor, openstack_id, openstack_ports, openstack_region, openstack_tenant_id, openstack_tenant_name), openstack-floating-ip (manages a given floating IP), openstack-cinder-volume (attach / detach a volume to / from a node).