Adding Config GUIs to the Modlist

To add an Config GUI to the modlist, run this in your ClientSetup:

    private void clientSetup(final FMLClientSetupEvent event) {
        ModLoadingContext.get().registerExtensionPoint(ConfigGuiHandler.ConfigGuiFactory.class,
                () -> new ConfigGuiHandler.ConfigGuiFactory((mc, screen) -> {
                    return new ConfigGui(screen);
                }));
   }