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.
In deploy, targetName is converted using filenameToWebContextMapper.convertDeploymentTargetNameToContext(targetName), but here it's not. I'm not sure what values targetName may take (before or after conversion), but this appears to mean that for the same artifact, you'd need to supply a different value of targetName to undeploy than provided to deploy