Ensure support for external gossip (external network nodes)

[jeromy-cannon]

we need to support external IP address for the network-node(x) service, the current solution does not provide that. This is so that an external consensus node can gossip with consensus nodes running within a fullstack-deployment k8s cluster.

We should also allow a domain name to be passed in to be used to build the config.txt (and genesis-network.json)

• requires Charts[Network]: Ensure support for external gossip (external network nodes) full-stack-testing#850