changes to explicitly advance the modals after google oauth credentials ...

...are received and to completely remove the problematic connecting state #1841

A good chunk of this diff is the byproduct of cleaning up unused arguments to constructors...will comment.
Yeah we create uninvited, open download users in XmppAvailableServlet. So the internal state "not invited" thing is really just a relic that's not used for anything, so we can remove it any time. I just moved that chunk of code from XmppConnector, but that line isn't really necessary.