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
break;
        }
        case RPCArg::Optional::OMITTED_NAMED_ARG: {
            ret += ", optional"; 
            break;
        }
        case RPCArg::Optional::NO: {
            ret += ", required";
            break;
        }
            
        }
    }
    ret += ")";
    ret += m_description.empty() ? "" : " " + m_description;
    return ret;
}
std::string RPCArg::ToStringObj(const bool oneline) const
{
    std::string res;
    res += "\"";
    res += m_name;
    if (oneline) {
        res += "\":";
    } else {
        res += "\": ";
    }
    switch (m_type) {
    case Type::STR: