Input: UDP Client to provide motion and touch controls

An implementation of the cemuhook motion/touch protocol, this adds the
ability for users to connect several different devices to citra to send
direct motion and touch data to citra.

Co-Authored-By: jroweboy <jroweboy@gmail.com>

src/core/settings.h

@@ -401,6 +401,9 @@ struct Values {
     std::string motion_device;
     TouchscreenInput touchscreen;
     std::atomic_bool is_device_reload_pending{true};
+    std::string udp_input_address;
+    u16 udp_input_port;
+    u8 udp_pad_index;
 
     // Core
     bool use_multi_core;