Bug 383571

Usecase:
- Activities in Plasma can be used to start/stop a bundle of software related to... an activity (like e.g. "work")
- Upon stop, Activities stop all possible software (mostly only KDE software) and keep the session "in mind"
- Upon restart, Activities restart all software previously stopped. This works  seemingly just like a Plasma session exit/restart when open software are set to be memorised.

Issue with RKWard:
- When asked to be terminated by the system, RKWard wants to know what to do with the workspace and opens a dialog to Save/Discard/Don't quit.
- This actually "suspend" the stopping of the Activity, rendering the whole start/stop of Activities useless when using RKWard, because one has to stop all RKWard windows before stopping the activity, then manually restore them.
- Incidentally, this also concerns the stopping/restarting of Plasma sessions, as RKWard behave the same in that case (it stops the session deconnection to ask what to do with the workspace)

Proposition:
- This behaviour makes sense as a default, because it is not easy to guess the user's workflow with workspace and how valuable the workspace is to the user
- But having a way to provide RKWard with the information about what to do upon termination would be nice for this particular usecase
- A possibility would be to implement 3 possible behaviour on termination as a setting:
   1/ Always ask what to do with the workspace and thus suspend termination (current behaviour and sensible default)
   2/ Always save the workspace
   3/ Never save the workspace