Allow for Complete and Closed groupings to be re-ordered just like the items inside them

Currently you can only drag and drop the items within each group on the Statuses screen. This means that Closed always appears before Complete for me and that's annoying as I want it to be last. I can't drag and drop it like I can with individual items inside.

It's quite misleading too since the Complete appears before it on the Admin page but then in the Roadmap screen it's after.