Removing any mention of USGSwsDataRetrieval

@dlorenz-usgs : I'm getting multiple requests for help with scripts or packages that are breaking because they call USGSwsBase, which still imports USGSwsDataRetrieval...calling the same function names as dataRetrieval (or vice versa). It's a mess. So, let's try to clean this up so we can at least install USGSwsBase (or change the name right now to smwrBase?) via install_github.

Want me to move findSites and to dataRetrieval? It's basically a wrapper for whatNWISsites. I like the added filters.