Drops the deleted and restored handlers in ThreadObserver in favour of reconciling category stats and FKs in the DeleteThread and RestoreThread requests
Changes the post view so that in soft-deleted threads, posts appear as if they have been soft-deleted too
Changes thread actions in the frontend to include a "Permanently delete" button when the thread is already soft-deleted so that restoring first is no longer necessary
This PR does the following:
deletedandrestoredhandlers in ThreadObserver in favour of reconciling category stats and FKs in the DeleteThread and RestoreThread requests