Raspberry Pi support

[WildWeazel]

This is more of a "for future reference" than an actual feature request, but as of 4.2.1 Godot now officially supports exporting to RPi: https://github.com/godotengine/godot-proposals/issues/988

If someone wants to look into it, see what we need as far as export settings and templates, action script, and so on. I have a RPi 4 available for testing.

[WildWeazel]

Technically the target is "arm64 Linux" and not specifically the RPi platform, so it would also apply to eg. arm64 Chromebooks. I also have one of those, if I can un-brick it :)