Ensure the Collection has enough information about Ruby facts to cache their output

Currently only caching of core facts is supported. Since this is done based on resolvers, the internal process for caching Ruby facts might look quite different. This ticket is intended to track the investigation of what work would be needed to allow the caching of Ruby facts by name, analogous to the UX of caching by group name for core facts. That work also includes updating the command line option which lists cachable facts to include Ruby facts.