For every peer expose through `getpeerinfo` RPC whether or not we selected them as HB peers, and whether or not they selected us as HB peers.

Suggestion by @gmaxwell.
{
    LOCK(cs_vNodes);
    if (CNode* pnode = FindNode(strNode)) {
        pnode->fDisconnect = true;
        return true;
    }
    return false;
}
bool CConnman::DisconnectNode(const CSubNet& subnet)
{
    bool disconnected = false;
    LOCK(cs_vNodes);
    for (CNode* pnode : vNodes) {
        if (subnet.Match(pnode->addr)) {
            pnode->fDisconnect = true;
            disconnected = true;
        }
    }
    return disconnected;
}
bool CConnman::DisconnectNode(const CNetAddr& addr)
{
    return DisconnectNode(CSubNet(addr));
}
bool CConnman::DisconnectNode(NodeId id)