Subnav needs a refactor to support more use cases

[pat270]

There are more use cases for subnav that I wasn't aware of. It needs a refactor to support the case in [Lexicon 2] Search in Management Bar. This is a breaking change although I don't think anyone is using this component at this time.

[pat270]

I'm leaning toward scrapping the subnav component all together and using the tbar component with variation to create this. I don't think is that serious of a breaking change, but let me know what you guys think.