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);
    for (CNode* pnode : vNodes) {
        if (subNet.Match(static_cast<CNetAddr>(pnode->addr))) {
            return pnode;
        }
    }
    return nullptr;
}
CNode* CConnman::FindNode(const std::string& addrName)
{
    LOCK(cs_vNodes);
    for (CNode* pnode : vNodes) {
        if (pnode->GetAddrName() == addrName) {
            return pnode;
        }
    }
    return nullptr;
}
CNode* CConnman::FindNode(const CService& addr)
{
    LOCK(cs_vNodes);
    for (CNode* pnode : vNodes) {
        if (static_cast<CService>(pnode->addr) == addr) {
            return pnode;
        }
    }
    return nullptr;
}
bool CConnman::AlreadyConnectedToAddress(const CAddress& addr)