Undo last previous action button

[Buckminsterfullerene02]

If you make an action such as mod or profile deletion by accident and you don't know what it was you deleted (as mentioned in #78), it would be nice to have an emergency "oh shit go back" button.

I'm sure this would rely on #13 to be robust...

... but since the only good action I can think of that this is useful for is profile or mod deletion, maybe some shitter, bodge solution with a temp value of whatever it was that was deleted being stored for the undo button would be good enough.