Graphical User Interface (GUI) for DVUploader

@donsizemore and I were just chatting about how to make it easier for curators to upload files into Dataverse via API and at http://irclog.iq.harvard.edu/dataverse/2019-08-09#i_102387 I asked if they want a GUI. Our feeling is that a GUI would be very popular but I have no idea how hard it would be to add one to DVUploader. Ideally the GUI would work on Windows, Mac, and Linux.