DolphinQt2: Add missing Q_OBJECT macro to all QObject-related classes missing it

Without this macro, if any signals or slots were attempted to be used,
they wouldn't work; neither would various other features of the Qt
meta-object system. This can also lead to weird behavior in other
circumstances. Qt's documentation specifically states:

"Therefore, we strongly recommend that all subclasses of QObject use the
Q_OBJECT macro regardless of whether or not they actually use signals,
slots, and properties."

on its page for "The Meta-Object System", which can be seen here:
https://doc.qt.io/qt-5/metaobjects.html

Let's opt for "always do the right thing", and keep the code extensible
for the future and not have random things blow up on us.

Source/Core/DolphinQt2/Config/Mapping/GCKeyboardEmu.h

@@ -15,6 +15,7 @@ class QVBoxLayout;
 
 class GCKeyboardEmu final : public MappingWidget
 {
+  Q_OBJECT
 public:
   explicit GCKeyboardEmu(MappingWindow* window);
 

Source/Core/DolphinQt2/Config/Mapping/GCMicrophone.h

@@ -15,6 +15,7 @@ class QVBoxLayout;
 
 class GCMicrophone final : public MappingWidget
 {
+  Q_OBJECT
 public:
   explicit GCMicrophone(MappingWindow* window);
 

Source/Core/DolphinQt2/Config/Mapping/GCPadEmu.h

@@ -15,6 +15,7 @@ class QVBoxLayout;
 
 class GCPadEmu final : public MappingWidget
 {
+  Q_OBJECT
 public:
   explicit GCPadEmu(MappingWindow* window);
 

Source/Core/DolphinQt2/Config/Mapping/GCPadWiiUConfigDialog.h

@@ -13,6 +13,7 @@ class QVBoxLayout;
 
 class GCPadWiiUConfigDialog final : public QDialog
 {
+  Q_OBJECT
 public:
   explicit GCPadWiiUConfigDialog(int port, QWidget* parent = nullptr);
 

Source/Core/DolphinQt2/Config/Mapping/Hotkey3D.h

@@ -10,6 +10,7 @@ class QHBoxLayout;
 
 class Hotkey3D final : public MappingWidget
 {
+  Q_OBJECT
 public:
   explicit Hotkey3D(MappingWindow* window);
 

Source/Core/DolphinQt2/Config/Mapping/HotkeyDebugging.h

@@ -10,6 +10,7 @@ class QHBoxLayout;
 
 class HotkeyDebugging final : public MappingWidget
 {
+  Q_OBJECT
 public:
   explicit HotkeyDebugging(MappingWindow* window);
 

Source/Core/DolphinQt2/Config/Mapping/HotkeyGeneral.h

@@ -10,6 +10,7 @@ class QHBoxLayout;
 
 class HotkeyGeneral final : public MappingWidget
 {
+  Q_OBJECT
 public:
   explicit HotkeyGeneral(MappingWindow* window);
 

Source/Core/DolphinQt2/Config/Mapping/HotkeyGraphics.h

@@ -10,6 +10,7 @@ class QHBoxLayout;
 
 class HotkeyGraphics final : public MappingWidget
 {
+  Q_OBJECT
 public:
   explicit HotkeyGraphics(MappingWindow* window);
 

Source/Core/DolphinQt2/Config/Mapping/HotkeyStates.h

@@ -10,6 +10,7 @@ class QHBoxLayout;
 
 class HotkeyStates final : public MappingWidget
 {
+  Q_OBJECT
 public:
   explicit HotkeyStates(MappingWindow* window);
 

Source/Core/DolphinQt2/Config/Mapping/HotkeyTAS.h

@@ -10,6 +10,7 @@ class QHBoxLayout;
 
 class HotkeyTAS final : public MappingWidget
 {
+  Q_OBJECT
 public:
   explicit HotkeyTAS(MappingWindow* window);
 

Source/Core/DolphinQt2/Config/Mapping/HotkeyWii.h

@@ -10,6 +10,7 @@ class QHBoxLayout;
 
 class HotkeyWii final : public MappingWidget
 {
+  Q_OBJECT
 public:
   explicit HotkeyWii(MappingWindow* window);
 

Source/Core/DolphinQt2/Config/Mapping/WiimoteEmuExtension.h

@@ -11,6 +11,7 @@ class QHBoxLayout;
 
 class WiimoteEmuExtension final : public MappingWidget
 {
+  Q_OBJECT
 public:
   enum class Type
   {

Source/Core/DolphinQt2/Config/Mapping/WiimoteEmuGeneral.h

@@ -7,10 +7,12 @@
 #include "DolphinQt2/Config/Mapping/MappingWidget.h"
 
 class QComboBox;
+class QHBoxLayout;
 class WiimoteEmuExtension;
 
 class WiimoteEmuGeneral final : public MappingWidget
 {
+  Q_OBJECT
 public:
   explicit WiimoteEmuGeneral(MappingWindow* window, WiimoteEmuExtension* extension);
 

Source/Core/DolphinQt2/Config/Mapping/WiimoteEmuMotionControl.h

@@ -15,6 +15,7 @@ class QVBoxLayout;
 
 class WiimoteEmuMotionControl final : public MappingWidget
 {
+  Q_OBJECT
 public:
   explicit WiimoteEmuMotionControl(MappingWindow* window);