Feature request: touchscreen joystick on full screen HUD

With 500mw radio telemetry there is no needs in old heavy/ugly radio controllers.
And it would be great to make full FPV station from almost any tablet computer.
Hud with touch screen may looks like this:
with scalable/draggable joysticks on sides of the screen. and camera tilt and pan sliders in some radius on center of the hud, with center camera button in center of screen.
And it needs some action buttons. Like RTL or flying mode selection. Retract release button, maybe.
P.S. if developers thinking about safety flying. make that joysticks working only in semiautomatic flying modes. like loiter or poshold.
And who cant feels contols on touch can use physical joysticks like 

No implementation files, tests, or entry points are named. Start by reviewing Mission Planner's existing full-screen HUD and input controls, then clarify the joystick, camera, and action-button scope and safety behavior. Done should include an agreed touchscreen HUD design and working implementation across the requested controls.

Written by the indexing model from the issue text.