Tilt improvements: Add visualizer, better defaults

[hrydgard]

Helps #16881

Turns out it was nearly impossible to understand how tilt controls worked without a visualizer, so I added one.

And it was revealed that my understanding was wrong too (I didn't write the code originally), especially around calibration.

I'll followup with a change that will make it work better held at an angle. This will remove the Base Position setting and replace with just calibration.

Anyway, here's the first improvement to the UI, which already makes it much easier to configure:

[iota97]

There might be some minor issues with the translations, for example in Italian one:

Calibrate = Calibra il D-Pad
To Calibrate = Mantenere il dispositivo su una superficie piatta e premere "Calibra".

"To Calibrate" will ask to press "Calibra", but the button will actually be called "Calibra il D-Pad". Same with few other languages. Probably it's quite confusing it's referencing D-Pad here at all :/

[hrydgard]

It's not supposed to reference the D-Pad at all, dunno where that came from. I'll fix it.