Inbox (technical)

## The problem

There is the normal cover editing UI, and there is also a seperate editing UI for when mods review submissions. Both of these are very useful for different things (adding covers and general overview, and changing attributes like indexes and content ratings), and both of these use cases come up in both normal editing and in reviewing. However, each seperate thing is locked to it's own editor.

## The idea

Make it so in both editing and reviewing you can switch between the two UIs. Both would default to the one they have now, but by having the option to switch, it can make certain edits easier on both pages. Hopefully this change also wouldn't be too much work because it's just copy-pasting things and then adding a toggle, but maybe it's more difficult than I think.