configure_input: Hook up the motion button and checkbox

This allows toggling motion on or off, and allows access to the motion configuration.
Also changes the [waiting] text for motion buttons to Shake! as this is how motion is connected to a player.

src/core/hle/service/hid/controllers/npad.cpp

@@ -389,7 +389,7 @@ void Controller_NPad::OnUpdate(const Core::Timing::CoreTiming& core_timing, u8*
         // Try to read sixaxis sensor states
         std::array<MotionDevice, 2> motion_devices;
 
-        if (sixaxis_sensors_enabled) {
+        if (sixaxis_sensors_enabled && Settings::values.motion_enabled) {
             sixaxis_at_rest = true;
             for (std::size_t e = 0; e < motion_devices.size(); ++e) {
                 const auto& device = motions[i][e];

src/core/settings.h

@@ -152,6 +152,7 @@ struct Values {
 
     bool vibration_enabled;
 
+    bool motion_enabled;
     std::string motion_device;
     std::string touch_device;
     TouchscreenInput touchscreen;