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

std::string blockfilterindex_value = args.GetArg("-blockfilterindex", DEFAULT_BLOCKFILTERINDEX);
    if (blockfilterindex_value == "" || blockfilterindex_value == "1") {
        g_enabled_filter_types = AllBlockFilterTypes();
    } else if (blockfilterindex_value != "0") {
        const std::vector<std::string> names = args.GetArgs("-blockfilterindex");
        for (const auto& name : names) {
            BlockFilterType filter_type;
            if (!BlockFilterTypeByName(name, filter_type)) {
                return InitError(strprintf(_("Unknown -blockfilterindex value %s."), name));
            }
            g_enabled_filter_types.insert(filter_type);
        }
    }
    
    if (args.GetBoolArg("-peerblockfilters", DEFAULT_PEERBLOCKFILTERS)) {
        if (g_enabled_filter_types.count(BlockFilterType::BASIC) != 1) {
            return InitError(_("Cannot set -peerblockfilters without -blockfilterindex."));
        }
        nLocalServices = ServiceFlags(nLocalServices | NODE_COMPACT_FILTERS);
    }
    
    if (args.GetArg("-prune", 0)) {
        if (args.GetBoolArg("-txindex", DEFAULT_TXINDEX))
            return InitError(_("Prune mode is incompatible with -txindex."));
        if (!g_enabled_filter_types.empty()) {
            return InitError(_("Prune mode is incompatible with -blockfilterindex."));
        }
    }