Currently the `getnetworkinfo` returns something like: 

```
"localservices": "0000000000000449",
```

Manually parsing this consistently gives me a headache (see also https://github.com/sipa/bitcoin-seeder/pull/77).

It would be useful to parse this and show the right combination of `NODE_NETWORK`, `NODE_GETUTXO`, `NODE_BLOOM`, `NODE_WITNESS`, `NODE_NETWORK_LIMITED` and `NODE_COMPACT_FILTERS`. In addition the help text for `getnetworkinfo` could be expanded to mention the right BIP numbers for known flags.

There is some ad hoc parsing to populate e.g. `localrelay`, etc (?).  Their help text could also refer back to `NODE_GETUTXO`.

See also: https://en.bitcoin.it/wiki/Protocol_documentation#Network_address
"  ,...\n"
            "]\n"
                },
                RPCExamples{
                    HelpExampleCli("getaddednodeinfo", "\"192.168.0.201\"")
            + HelpExampleRpc("getaddednodeinfo", "\"192.168.0.201\"")
                },
            }.Check(request);
    if(!g_connman)
        throw JSONRPCError(RPC_CLIENT_P2P_DISABLED, "Error: Peer-to-peer functionality missing or disabled");
    std::vector<AddedNodeInfo> vInfo = g_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);