Implement OSTF tests for ceilometer metrics for Fuel for OpenStack

Create OSTF tests for ceilometer notifications: - Nova: memory, vcpus, disk.root.size, disk.ephemeral.size - Neutron: network, network.create, network.update, subnet, subnet.create, subnet.update, port, port.create, port.update, router, router.create, router.update, ip.floating.create, ip.floating.update - Glance: i...