Alarm over the time

The use cases behind this blueprint are:

* I don't want to receive the alarm callback during a certain time lapse.
* I want to trigger a alarm action every three hours if the/an_other alarm have a particular state.

The idea is to create a new kind of alarm rule on the API part, and a new alarm evaluator that change state and trigger alarms actions over the time.

Combining this kind alarm with an other alarm should be tricks.