Stop quitting deletion of closed projects

* Deleting closed projects is currently impossible due to a number of
  checks taking place that assume the project is open.

* Any attempt to use the API folder.members() results in an exception
  for a closed project. Need to avoid this and return a sane result

* RelateResourceFinder
* PreviewManager
* UdfManager
 * Checks the given resource is not a closed project. If it is then bail
   out with a sensible result

* VdbUiRefactorHandler
 * Check for closed project since getProjectFileResources also throws
   same exception as folder.members()

* RefactorResourceUtils
 * Modify check methods to sanely handle closed projects
 *


* PreviewManager
 *