Thread:Feedback/Moved/deletion messages

Moved/deletion messages should assume the sortkey of the message they are referring to… Move or delete a highly placed thread and you get a highly placed notice, move or delete something old you should get a burred notice.

This might also make it easier to preserve a posts sortkey if its moved back. I.e. if you move a thread, it's bumped at the new location but if you move it back it retains the location it originally had (and potentially erases its own move notice). This would make disputes about moving less disruptive.