Provide regex based category validation for CategoryRoutedAliases

This ticket will add the check to enforce a (configurable, optional) regular expression to enreject requests that attempt to add an unexpected category, or a malformed category to a category routed alias. The purpose of this check is to provide a safety valve to ensure that unexpected data values don't cause creation of collections inconsistent with the user's intended design. This check should happen within the validateRouteValue() method specified by RoutedAlias