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.
{
    NodeContext& node = EnsureNodeContext(request.context);
    if(!node.connman)
        throw JSONRPCError(RPC_CLIENT_P2P_DISABLED, "Error: Peer-to-peer functionality missing or disabled");
    std::vector<AddedNodeInfo> vInfo = node.connman->GetAddedNodeInfo();
    if (!request.params[0].isNull()) {
        bool found = false;
        for (const AddedNodeInfo& info : vInfo) {
            if (info.strAddedNode == request.params[0].get_str()) {
                vInfo.assign(1, info);
                found = true;
                break;
            }
        }
        if (!found) {
            throw JSONRPCError(RPC_CLIENT_NODE_NOT_ADDED, "Error: Node has not been added.");
        }
    }
    UniValue ret(UniValue::VARR);
    for (const AddedNodeInfo& info : vInfo) {
        UniValue obj(UniValue::VOBJ);
        obj.pushKV("addednode", info.strAddedNode);
        obj.pushKV("connected", info.fConnected);
        UniValue addresses(UniValue::VARR);
        if (info.fConnected) {
            UniValue address(UniValue::VOBJ);
            address.pushKV("address", info.resolvedAddress.ToString());
            address.pushKV("connected", info.fInbound ? "inbound" : "outbound");
            addresses.push_back(address);
        }