Display the user that aborted a workrequests in the web interface

When a workrequest is actively aborted by a user, the database records the id in aborted_by_id, so we do have this knowledge, but it is not made available on the web interface. There isn't always a user performing an abort, it can also be a disconnecting worker. Still it would be nice to have this shown when available. A possible way could be hovering the "Aborted" text to avoid cluttering the view.