Alert Targets should have the ability to contain an unstructured set of properties so that customer defined targets (and dispatchers) can still be stored and retrieved by Ambari.
The initial design had a defined structure for both email and snmp protocols. However, these properties were just turned into a flat set by the data layer.
For the initial approach, it doesn't make much sense to try to model structured properties when, at the end of the day, they need to be serialized to a map.
This also lets any property defined be passed to the backend provider in order to properly dispatch to the targets.