3DR Radios no longer exist

Domain changes for the ArduPilot locations from DIYDrones to
ArduPilot.org

- Added new Advanced visualization

I removed some needed headers from a top level file which then causes a
ripple effect downstream

Also additional major Mission usability changes

Removed commented v4 ArduPilot Quad fw links

To address issue https://github.com/mavlink/qgroundcontrol/issues/2735

This was causing problems with auto-connect after a flash

This provides a better workflow for firmware upgrade

- Also fix vehicle selector dropdown in toolbar

Add scroll height indicators to Flickable

The lines removed set the center point of the throttle axis to one extreme of the joystick range. This causes an offset value when the stick is centered if the joystick does not return exactly zero. This is important for vehicles with reversible throttle, such as ground robots or boats.

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