Add option for Never Hide Mouse Cursor

Instead of having a single GUI checkbox for "Always Hide Mouse Cursor",
I have instead opted to use radio buttons so the user can swap between
different states of mouse visibility. "Movement" is the default
behavior, "Never" will hide the mouse cursor the entire time the game is
running, and "Always" will keep the mouse cursor always visible.

Source/Core/DolphinQt/Settings/InterfacePane.h

@@ -8,6 +8,7 @@
 class QCheckBox;
 class QComboBox;
 class QLabel;
+class QRadioButton;
 class QVBoxLayout;
 
 class InterfacePane final : public QWidget
@@ -23,6 +24,9 @@ private:
   void ConnectLayout();
   void LoadConfig();
   void OnSaveConfig();
+  void OnCursorVisibleMovement();
+  void OnCursorVisibleNever();
+  void OnCursorVisibleAlways();
 
   QVBoxLayout* m_main_layout;
   QComboBox* m_combobox_language;
@@ -43,6 +47,8 @@ private:
   QCheckBox* m_checkbox_enable_osd;
   QCheckBox* m_checkbox_show_active_title;
   QCheckBox* m_checkbox_pause_on_focus_lost;
-  QCheckBox* m_checkbox_hide_mouse;
+  QRadioButton* m_radio_cursor_visible_movement;
+  QRadioButton* m_radio_cursor_visible_never;
+  QRadioButton* m_radio_cursor_visible_always;
   QCheckBox* m_checkbox_lock_mouse;
 };