Fold prop#196 and prop#217 into torspec

Right now there is a proposal 196 named "Extended ORPort and TransportControlPort" and a proposal 217 named "Tor Extended ORPort Authentication", both in status "Finished".

So, (a) that ExtORPort thing, not just the auth part but the whole thing, isn't specified in any Tor spec, just in the proposals/ directory.

and also (b) that TransportControlPort part never got built, and probably shouldn't be built (we could imagine that instead we should do all of those things using the stdin/stdout channel between Tor and the PT), so "Finished" is misleading there.