Survey UI: Units

The units in both v and v2 survey interfaces are metric. These should change with the units selected for the Planner. Generated units such as cam_trigg_dist and waypoint altitudes will be interpreted in feet and not meters if the Planner is in meters. It would be _really_ nice if the survey interface could actually display the correct units, but if not, listing no units would be better than listing the wrong unit.

Start by locating the v and v2 survey interfaces and the Planner unit-selection handling. Check how cam_trigg_dist and waypoint altitudes are displayed and generated when meters are selected; done means they use the selected units, or omit units rather than showing incorrect metric labels.

Written by the indexing model from the issue text.