Reduce recusion to save stack space

[qwelyt]

In places like

waddle/firmware/waddle/src/state.rs

Lines 96 to 103 in e7d38b8

	fn get_key(position: &Position, layer: u8) -> Option<Key> {
	match LAYOUT.get_key(layer, position) {
	Key::KeyCode(kc) => Some(Key::KeyCode(kc)),
	Key::Function(f) => Some(Key::Function(f)),
	Key::PassThrough(go_down) => State::get_key(position, layer - go_down),
	_ => None
	}
	}

there is a recursion happening, wasting stack space.

As the stack is quite limited it would be good to rewrite this part (and others like it) to remove the recursion. Do a loop instead.