XDMoD Plugin: action on allocation reaching resource limit

[dsajdak]

For resources using the XDMoD plugin, an action needs to happen when a limit is approaching and reached. Similar to an allocation expiration date approaching and reached. It would be nice if this were configurable as all centers have different policies.
Examples include:

• CPU hour attribute approaches X% used, send email notification to allocation users
• CPU hour attribute reaches 100%, send email to allocation users and system staff
• Storage quota limit approaches Y%, used, send email notification to allocation users
• Storage quota limit reaches 100% send email notification to allocation users

There should be a way to disable these notifications on the allocation level