Task #10811: fixed previous (accidental too early) commit. added function resource_monitoring.check_new_claim_for_conflicts which is also called from the one and only resource_claim trigger

Task #10811: made resource_usage table and view, and made trigger functions which automatically fill/update/clean the resource_usage table whenever a resource _claim is inserted/updated/deleted

Task #10811: added initial skeleton for trigger method check_claims_after_resource_claim_insert_or_update

Task #8887: modified specification update trigger to check for min_starttime, swap start-endtime, etc

Task #9309: added conflict_reasons, task and resource_claim relations. Added initial storage and bandwith set of conflict reasons. Added triggers to ensure db consistancy on task and resource_claim conflict status

Task #8887: added trigger function which deletes resource_claims for task when the task is updated to approved status