### FEATURE REQUEST

Currently, when a bitcoin node is set up with a connection to both TOR and normal IPv4/6 internet, the 8 outbound-only connection slots, almost always get filled with nodes connecting over IP.
Adding a config option, which would try to ballance these connections based on what kind of network they go through, would be benefficial in many ways:

1. It would add edges between bitcoin network on TOR and normal internet, reducing delays, and the risks associated with an attacker isolating a part of TOR-bitcoin-network from the rest of the world
(Or an ISP/government man-in-the-middling all the normal IP connections)

2. It would help hide/annonymise normal user's transactions from his/her ISP, by mixing them with TOR-outbound ones

3. It would reduce the stress on normal general purpose TOR exit nodes, as users would more likely/reliably connect to TOR-IPv4/6 bitcoin nodes instead of exiting into normal internet first, and then connecting to default IPv4/6-only bitcoin nodes

I understand it is possible to create such bridges already, by forcing connections to TOR-only nodes, or by just running a node with lots of inbound slots, but I think the proposed option, would greatly increase the number of such relays, and remove the need for user to maintain a TOR-node whitelist, by handing this work off to normal bitcoind connection finding algorithm.

This could be implemented as a minimum number of connections for each network, or just a simple evening boolean switch. (Which could be enabled by default for bitcoind installs with TOR connectivity)

In the future, if bitcoin was to support a new network type (for example cjdns/I2P/GNUnet), this option would help establish a presence on the new network faster

bitcoind: 0.15
id(idIn),
      nLocalHostNonce(nLocalHostNonceIn),
      m_conn_type(conn_type_in),
      nLocalServices(nLocalServicesIn)
{
    if (inbound_onion) assert(conn_type_in == ConnectionType::INBOUND);
    hSocket = hSocketIn;
    addrName = addrNameIn == "" ? addr.ToStringIPPort() : addrNameIn;
    if (conn_type_in != ConnectionType::BLOCK_RELAY) {
        m_tx_relay = std::make_unique<TxRelay>();
    }
    if (RelayAddrsWithConn()) {
        m_addr_known = std::make_unique<CRollingBloomFilter>(5000, 0.001);
    }
    for (const std::string &msg : getAllNetMessageTypes())
        mapRecvBytesPerMsgCmd[msg] = 0;
    mapRecvBytesPerMsgCmd[NET_MESSAGE_COMMAND_OTHER] = 0;
    if (fLogIPs) {
        LogPrint(BCLog::NET, "Added connection to %s peer=%d\n", addrName, id);
    } else {
        LogPrint(BCLog::NET, "Added connection peer=%d\n", id);
    }
    m_deserializer = std::make_unique<V1TransportDeserializer>(V1TransportDeserializer(Params(), GetId(), SER_NETWORK, INIT_PROTO_VERSION));
    m_serializer = std::make_unique<V1TransportSerializer>(V1TransportSerializer());
}
CNode::~CNode()
{
    CloseSocket(hSocket);
}
bool CConnman::NodeFullyConnected(const CNode* pnode)