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.
good catch on NPE, have done that

agree would be nice to improve `DependentConfiguration` with this -- but that is a big task in its own right.  i have added TODO comments in both classes referencing each other for that.