add trashbin restore scenarios for when the original folder has been deleted

[phil-davis]

See comment cs3org/reva#1795 (comment)

We want to test what happens when a whole folder tree has been deleted, then the trashbin restore API is used to restore just 1 file or a whole sub-folder from within the deleted folder tree, and without specifying the location to restore it to.

Does the oC10 server automatically create the previous top-level folders needed? Or the item is restored to the root of the user's file system? Or an error status is returned because the target folder tree for the restore does not exist? Or?