This is done by:
1) Implementing said protocol in a new controller input class CemuHookUDPServer.
2) Adding functionality in the WiimoteEmu class for pushing that motion input to the emulated Wiimote and MotionPlus.
3) Suitably modifying the UI for configuring an Emulated Wii Remote.
Settings that come from the SYSCONF are now included in Dolphin's
config system as part of the base layer. They are handled in a
special way compared to other settings to make sure they are only
loaded from and saved to the SYSCONF (to avoid different, possibly
contradicting sources of truth).