Kube test network : Start prom/grafana metrics services

@fraVlaca and @davidkel have done some great work wiring up Prometheus / Grafana services in the test-network and bare-metal networks derived from fabric-test-operator.

Tracking time-series metrics of system behavior is great. It's virtually impossible to do any useful diagnosis and/or benchmarking on a distributed system without the ability to correlate "what happened" and "when did it happen" at a system-wide level.

Carry forward the metrics work by setting up a yaml descriptor and ingress to launch prom/grafana on the kube test network. This will allow us to poke + prod Fabric networks with a consistent lens across the different runtime platforms.

Maybe:
```
./network viz
```
or
```
./network metrics
```
?