Ref T10917. Converts web UI edits to transactions.

This is about 95% "the right way", and then I cheated on the last 5% instead of building a real EditEngine. We don't need it for anything else right now and some of the dialog workflows here are a little weird so I'm just planning to skip it for the moment unless it ends up being easier to do after the next phase (mail notifications) or something like that.