enable-tor: When run as a regular user, test a connection back to the hidden service...

enable-tor: When run as a regular user, test a connection back to the hidden service over tor.

This way we know that after enable-tor, the tor hidden service is fully
published and working, and so there should be no problems with it at
pairing time.

It has to start up its own temporary listener on the hidden service. It
would be nice to have it start the remotedaemon running, so that extra
step is not needed afterwards. But, there may already be a remotedaemon
running, in communication with the assistant and we don't want to start
another one. I thought about trying to HUP any running remotedaemon, but
Windows does not make it easy to do that. In any case, having the user
start the remotedaemon themselves lets them know it needs to be running
to serve the hidden service.

This commit was sponsored by Boyd Stephen Smith Jr. on Patreon.