Form edits are lost when coming back from settings

[wbazant]

Follow-up from #545. I claim this is a bug but a small one

[wbazant]

See also: #604 about going back from add location

[wbazant]

Instead of saving the intermediate state of the form, we can also not go back to forms but to the location page or to the map instead - let opening settings dismiss edits.

I've learned it's quite laborious to keep the intermediate state of the form for just the right context, and the feature of 'you can go to settings and change map type, and go back to editing' is not something anyone asked for - I just half-introduced it when thinking about the 'back from settings' destinations.