Fixes #6444 - add support for virtual NICs

ticket created https://tickets.puppetlabs.com/browse/FACT-691

It's not only for discovery, discovery image is currently the only system that has these custom facts built-in. I don't think we should extend puppet fact parser from discovery plugin, this is generic, people may want to use other implementations for these facts, until there are official fact names we can support these names at least. This is just a way how users can create IPMI devices based on facts.