To be able to label incoming tor connections as different from normal localhost connections in e.g. `getpeerinfo` and the peers list in the GUI it'd be useful to have them connect on an alternative local-only port. Or even better, a UNIX socket.

For manually set-up hidden services this would have to be configured manually and could add a `hsport` option or such. The external port would still appear as `XXXXXXXXX.onion:8333`, however internally it would redirect to a that port.

In the case of `torcontrol` this would be easy to set up automatically. It could add a new (localhost) binding port automatically and this code would have to be changed:
- https://github.com/bitcoin/bitcoin/blob/master/src/torcontrol.cpp#L441
- https://github.com/bitcoin/bitcoin/blob/master/src/torcontrol.cpp#L477

#if defined(HAVE_CONFIG_H)
#include <config/bitcoin-config.h>
#endif
#include <net.h>
#include <banman.h>
#include <clientversion.h>
#include <consensus/consensus.h>
#include <crypto/sha256.h>
#include <net_permissions.h>
#include <netbase.h>
#include <node/ui_interface.h>
#include <protocol.h>
#include <random.h>
#include <scheduler.h>
#include <util/strencodings.h>
#include <util/translation.h>
#ifdef WIN32
#include <string.h>
#else
#include <fcntl.h>
#endif
#ifdef USE_POLL
#include <poll.h>
#endif
#ifdef USE_UPNP