Allow granular targeting of Alarms

[mrgrain]

Description

Currently all alarms are classified into high and low severity. This is simple and works well for most cases. However in some situations it will be useful to target a specific alarm directly, e.g. to raise or decrease the severity for it.

Use Case

If I want to treat a high-severity alarm as a lower severity
If I want to treat a low-severity alarm as a higher severity
If I want a specific alarm to trigger an action that is different than the defaults for high or low