Execute Action at monitoring server failure.(deal with Issu 251)

Add a mechanism to do the action, when detected of the monitoring server failure (e.g. doesn't reply).

When Arm thread initializ, register trriger and monitoring server info to chashDB(sqlite).
when a failure was detected, Update the trigger and Register the event, and to perform the action(if registration).
TriggerID / Message Comment is a provisional value.

please confirm and comment.
In this usage, "Failed" is used as an intransitive verb and typically used as "failed in xxx-ing".
And the sentence is redundant because 'connect' appears twice.