Make pop-up abaout "Reference files available" and "Do you really want to finish" pop-up configurable

Currently the pop-up, that reference files exist, is always shown, after you open a task.

If this is the case should be configurable in Zf_configuration.

Same is true for the following pop-up:

• When you exit a task as a workflow-user, a pop-up is shown asking you, if you want to finish or just leave.
• After you click "finish" you are asked, if you really want to do that. If this second pop-up appears should also be configurable.