Consul stanza should allow different tags for nomad and nomad-client

Hi folks,

This is a feature request related to the `consul` stanza: https://www.nomadproject.io/docs/configuration/consul/#tags

We'd like to be register Nomad HTTP API in Fabio but unfortunately specifying Fabio tags in the `tags` field of the Consul stanza will have Fabio pick up http, serf and RPC ports:

There's the `nomad-client` service which gets registered and always points to `4646` but unfortunately because we can't separate the tags between client and server, we'll sometimes inherit `4647 or `4648` for example (see screenshot) when we really just want the HTTP API.

This is our `consul` stanza:

```json
{
"consul": {
"address": "127.0.0.1:8500",
"auth": null,
"auto_advertise": true,
"checks_use_advertise": true,
"client_auto_join": true,
"client_service_name": "nomad-client",
"server_auto_join": true,
"server_service_name": "nomad",
"tags": ["fabio-/nomad-client strip=/nomad-client"]
}
}
```

Cheers!