Add gamepad mapping DB from https://github.com/gabomdq/SDL_GameControllerDB

app/path.h

@@ -9,9 +9,12 @@ public:
 
     static QString getBoxArtCacheDir();
 
+    static QString getGamepadMappingFile();
+
     static void initialize(bool portable);
 
 private:
     static QString s_LogDir;
     static QString s_BoxArtCacheDir;
+    static const QString k_GameControllerMappingFile;
 };