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
if (isSubnet ? g_banman->IsBanned(subNet) : g_banman->IsBanned(netAddr)) {
            throw JSONRPCError(RPC_CLIENT_NODE_ALREADY_ADDED, "Error: IP/Subnet already banned");
        }
        int64_t banTime = 0; 
        if (!request.params[2].isNull())
            banTime = request.params[2].get_int64();
        bool absolute = false;
        if (request.params[3].isTrue())
            absolute = true;
        if (isSubnet) {
            g_banman->Ban(subNet, BanReasonManuallyAdded, banTime, absolute);
            if (g_connman) {
                g_connman->DisconnectNode(subNet);
            }
        } else {
            g_banman->Ban(netAddr, BanReasonManuallyAdded, banTime, absolute);
            if (g_connman) {
                g_connman->DisconnectNode(netAddr);
            }
        }
    }
    else if(strCommand == "remove")
    {
        if (!( isSubnet ? g_banman->Unban(subNet) : g_banman->Unban(netAddr) )) {
            throw JSONRPCError(RPC_CLIENT_INVALID_IP_OR_SUBNET, "Error: Unban failed. Requested address/subnet was not previously banned.");
        }
    }
    return NullUniValue;
}
static UniValue listbanned(const JSONRPCRequest& request)