Colour-code waypoints+rallypoints based on whether they are in sync with the vehicle

Currently I think it's too easy for waypoints and rally points to be out of sync between the ground station and the vehicle without the user realizing, which is potentially dangerous.

For now a quick improvement would be to colour code waypoints and rally points to show whether they are in sync with the vehicle or local. I'd use a much darker shade of the existing colours to indicate they are only in MP, and have points that are in sync with the vehicle use the existing brighter colours. You'd just need a dirty flag on each one, which is set whenever they are created, loaded or modified in MP, and cleared when uploaded or downloaded to the vehicle.

Further down the line I think we need to be more proactive in warning people if these points aren't in sync between MP and the vehicle, e.g. display a warning message if it detects the vehicle has gone into AUTO or RTL and you have unsynced waypoints/rallypoints.

I know there the Flight Data screen only shows the vehicle's state of these points, and that's what people should be looking at when operating, but it is still too easy to leave the view on the Flight Plan screen and think that is what it is going to do, because most other things in that view are updated live.

The issue names no files or tests. Start by locating the Flight Plan waypoint and rally-point creation, load, edit, upload, and download entry points, then trace how their display colours are chosen. Done means local-only points use darker existing colours, vehicle-synced points retain brighter colours, and the state updates after each listed operation.

Written by the indexing model from the issue text.