Deploy across an entire web cluster

Adds deploy, undeploy, and redeployAll to webapp cluster entities (DWAC and ControlledDWAC).

Also fixes some issues noticed in how tasks are tracked and displayed.
I worry about things like this - i.e. synchronizing on the entity. Other code might well synchronize on the entity for completely different reasons, so doing it here might lead to deadlock, depending what else the caller has done. If it's just a simple effector call we should be fine because that kicks off in a new thread.