Improve the speed of retrieving alarms by using a single query

Improve the speed of deleting an alarm definition by getting
all sub alarms for all alarms in a single query

Change alarm update to be atomic

Add comprehensive tests for AlarmMySqlRepositoryImpl

JAH-913 API fails to delete Alarm Definition when there are
lots of alarms

JAH-912 API fails listing alarms when there are lots of alarms

Change-Id: I7831f3ae40e713fc3671cfffeb46a2089d2de829