Remove processes and tasks when related document is deleted

add 3 listeners
1. listening to documents passed to "deleted" state (e.g moved to trash) => suspend process + task instances (+ make sure they do not appear anymore in the dashboard + adapt deleted doc workflow tab so that it's read-only)
2. listening to "delete permanently" actions to remove process + task instances + check that variables are also deleted
3. listening to "restore document" action to ree-nable process and its tasks