ability to control the Optional Consul service tags for each of the different nomad services

### Nomad version

`Nomad v0.9.4-rc1 (4999923574186583ce7a007865f745ecbc55ceb9)`

### Operating system and Environment details

`Red Hat Enterprise Linux Server release 7.6 (Maipo)`

### Issue

[ Conditional tag in query #671 ](https://github.com/hashicorp/consul/issues/671) is not yet supported.

I'm currently using the latest release candidate and was able to configure server.hcl to makes use of #5706
```
consul {
tags = [ "traefik.enable=true" ]
}
```

However traefik then configures my frontend-nomad `Host:nomad.xx.com` to each of the backend-nomad ports [ http (4646) | rpc (4647) | serf (4648) ] because each of these ports were also consul tagged traefik.enable=true.

I wish to consul tag [ "traefik.enable=true" ] only to the nomad http service port 4646.

### Reproduction steps

### Job file (if appropriate)

### Nomad Client logs (if appropriate)

### Nomad Server logs (if appropriate)

Start by tracing how the Consul configuration in server.hcl is applied to Nomad's HTTP, RPC, and Serf services. Determine how service tags are currently assigned across ports 4646, 4647, and 4648. Done means users can assign the requested tag only to the Nomad HTTP service, with coverage for the separate service-tag behavior.

Written by the indexing model from the issue text.