Add throttle gauge option to OSD

[MrD-RC]

Allow pilots to see the throttle as a vertical digital gauge. Similar appearance to the VSI vario gauge. Nothing shown is 0% throttle. 10 up arrows is full throttle. The element takes up 5 vertical characters.

Fixes https://github.com/iNavFlight/inav/issues/10723

Test

If anyone has a flight controller with a canvas OSD (FrSky PixelOSD). If they could confirm this is correct. It would be great. I plan on digging mine out when I have the time. But if someone beats me to it, I would be most grateful.

Requires Configurator https://github.com/iNavFlight/inav-configurator/pull/2354