For UrlCreatorSpecifications other than that corresponding to "Advanced URLs" UrlCreatorSpecification.createUrlFactory() returns `null`. (see: UrlCreatorSpecification (FirstSpirit Developer-API))
How to get a UrlFactory for UrlCreatorSpecification correspondig to a LegacyClass-UrlCreator (e.g. "Default URLs (SEO)", "Multiview URLs (SEO)", "Infix URLs (SEO)", "Default URLs", "Default URLs" or "Infix URLs")?
The goal is to provide a Renderer instance with a legacy UrlCreator - i.e. Renderer.urlFactory(UrlFactory corresponding to "Default URLs").
