Allow the Ceilometer Alarm to be used with cfn-push-stats

Allow the Ceilometer Alarm to be used with cfn-push-stats

This is for when:
- Ceilometer does not support the desired custom metric
- Easier migration to Ceilometer Alarms (reuse most of old templates)

A watchrule is create within the Ceilometer alarm, but it is marked
as belonging to Ceilometer. This is used in the follow situation:
- So we can figure out that we don't need to run the watch periodic task
- when we receive new sample data we can forward the data to Ceilometer

blueprint watch-ceilometer
Change-Id: I0d672e69a522a23158805d75378f4bfe631b4bf3