Fix bug in terrain transect adjustment

First and last points in transects did not have altitudes set correctly

Support PING response

SurveyMissionItem -> SurveyComplexItem

Safety summary: Rework to better match Safety Page

UnitsSettings: rework/bugfix metadata translators setup

Update terrain alts when user drags mission item

FactCheckBox: New value is not being set correctly

Don't allow user to add settings item command

Allow manual control of when to send FOLLOW_TARGET messages.

Different visuals for Planned Home in Plan View

Mission Item: Mavlink MAV_FRAME_GLOBAL_TERRAIN_ALT support

Limit output of camera and lights using brd_pwm_count

Use new FactValueSlider control for simple mission item altitudes