usbd: Implement usb backend system (#3737)

* initial impl

* reviews

* upstreamed deReaperJosh changes

* fixed config.cpp

---------

Co-authored-by: georgemoralis <giorgosmrls@gmail.com>

src/common/config.h

@@ -151,6 +151,10 @@ void setSysModulesPath(const std::filesystem::path& path);
 bool getLoadAutoPatches();
 void setLoadAutoPatches(bool enable);
 
+enum UsbBackendType : int { Real, SkylandersPortal, InfinityBase, DimensionsToypad };
+int getUsbDeviceBackend();
+void setUsbDeviceBackend(int value, bool is_game_specific = false);
+
 // TODO
 std::filesystem::path GetSaveDataPath();
 std::string getUserName();