This code handles the new ORPort options, and incidentally makes all
remaining port types use the new port configuration systems.

There are some rough edges!  It doesn't do well in the case where your
Address says one thing but you say to Advertise another ORPort.  It
doesn't handle AllAddrs.  It doesn't actually advertise anything besides
the first listed advertised IPv4 ORPort and DirPort.  It doesn't do
port forwarding to them either.

It's not tested either, it needs more documentation, and it probably
forgets to put the milk back in the refrigerator.