Add independent alarm report mechanism

Openstack need to add an independent fault alarm mechanism to facilitate the user to detect system problems. Alarm mechanism is currently provided in Ceilometer, but can not fully meet the requirements:
1. Ceilometer Alarm main objective is to single or multiple meter set thresholds to trigger heat autoscaling. For non-meter types of failures triggered alarms can not support.
2. Alarm is achieved by periodically polling meter value whether the user-defined threshold is reached, which can not meet the real-time requirements.
3. After triggering Alarm, there are two form of actions: http callback, log. Need to provide a real-time reporting method, such as SNMP interface.