Add an API for passing a signal through to a resource

Reuse the /waitcondition functionality to provide a
/signal pathway.
a signal could be a waitcondition or an alarm.

blueprint watch-ceilometer
Change-Id: Ia9da222b8072ee0dc65bf137e7d3eb7fa4d944f5
Make the current alarms use the signal action

blueprint watch-ceilometer
Change-Id: I7560650f207411ffaf14242bb74cdaf8acd0cf4b
Merge "Add an API for passing a signal through to a resource"
Merge "Make the current alarms use the signal action"