LPS-44342 Re-add methods, using new approach, as they are used by our plugins

This is the method from GenericPortlet:

public java.util.ResourceBundle More ...getResourceBundle(java.util.Locale locale) {
504		if (config == null)
505			throw new java.lang.IllegalStateException(
506					"Config is null, please ensure that your init(config) method calls super.init(config)");
507
508		return config.getResourceBundle(locale);
509	}