#4057 [HHQ-3715] Make agent schedule queue configurable

[Hyperic Team]

http://jira.hyperic.com/browse/HHQ-3715


Currently the agent scheduler in HQ is limited to a single thread which is responsible for sending out schedules. This was done to "throttle" the number of schedules sent out, but does have a couple of undesirable side-effects:

1) Any hang in scheduling can cause other metrics to not be scheduled. (Captured in HHQ-3694)


2) In a mass-schedule scenario, it can take minutes to potentially hours for agents to get their schedules

I think it would be a nice improvement if we could configure a thread pool that would be responsible for sending these schedules out. This would alleviate issues seen in #1 above with the added benefit of addressing IO bottlenecks from #2.