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

#include <util/threadnames.h>
#include <util/translation.h>
#include <validation.h>
#include <validationinterface.h>
#include <walletinitinterface.h>
#include <functional>
#include <set>
#include <stdint.h>
#include <stdio.h>
#ifndef WIN32
#include <attributes.h>
#include <cerrno>
#include <signal.h>
#include <sys/stat.h>
#endif
#include <boost/algorithm/string/replace.hpp>
#include <boost/signals2/signal.hpp>
#include <boost/thread/thread.hpp>
#if ENABLE_ZMQ
#include <zmq/zmqabstractnotifier.h>
#include <zmq/zmqnotificationinterface.h>
#include <zmq/zmqrpc.h>
#endif
static bool fFeeEstimatesInitialized = false;
static const bool DEFAULT_PROXYRANDOMIZE = true;
static const bool DEFAULT_REST_ENABLE = false;
static const bool DEFAULT_STOPAFTERBLOCKIMPORT = false;
#ifdef WIN32
#define MIN_CORE_FILEDESCRIPTORS 0
#else