Add an interface to configure Combos

[sago35]

Now it is possible to configure Combos from source code.

	// Combos
	combos := []keyboard.Combo{
		{
			Keys:      [4]keyboard.Keycode{jp.KeyQ, jp.KeyZ},
			OutputKey: jp.KeyMediaMute,
		},
		{
			Keys:      [4]keyboard.Keycode{jp.KeyW, jp.KeyX},
			OutputKey: jp.KeyMediaVolumeDec,
		},
		{
			Keys:      [4]keyboard.Keycode{jp.KeyE, jp.KeyC},
			OutputKey: jp.KeyMediaVolumeInc,
		},
		{
			Keys:      [4]keyboard.Keycode{jp.KeyR, jp.KeyV},
			OutputKey: jp.KeyMediaBrightnessDown,
		},
		{
			Keys:      [4]keyboard.Keycode{jp.KeyT, jp.KeyB},
			OutputKey: jp.KeyMediaBrightnessUp,
		},
	}
	for i, c := range combos {
		d.SetCombo(i, c)
	}

[sago35]

Since this PR changes the way data is stored in Flash, you need to initialize it using options like -tags reset_to_default.