Prevent DocumentRoutingEscalationAction to run concurrently

The DocumentRoutingEscalation bulk action is scheduled every 5min to execute escalation rules.
Concurrent execution of bulk action should be avoided, there is already a lock mechanism to avoid this but it works only partially.

The lock is set for 3 min when the bulk action is processing a record and prevent the listener to submit a new bulk command.
The problem is that the lock is set when the processing starts, but between bulk submit and processing there is the scroll that can take up to 6min for 50k match over 150m docs, so it is possible to schedule twice the bulk commands, resulting in concurrent updates overload and bad performance.

The bulk action needs to be set a exclusive, this will avoid concurrent execution.