Added unified token and proxy connection tracker and event generator

Tries to unify various ad-hoc means of connecting only when we have a valid proxy connection as well as refresh token for #1500. Can you give this a look @oxtoacart?

I think we also should at some point cleanup DefaultProxyTracker's "noProxies" lock condition. That's was a part of the old system for handling this, but that's now obsolete.