update ingress values and implementation

[vordimous]

Description

This improves the ingress controller to allow for managing ingress without a host specified. It also enables defining paths that can map to different ports down to the K8s zilla service. Additionally, it supports backward-compatible K8s versions of ingress.

Notes output with multiple ingress paths defined:

Zilla is available through an ingress controller at the base url(s):
  http://localhost/api
  http://localhost/ui

Notes output when no ingress is configured, the command dynamically forwards any exposed Zilla service ports:

Connect to Zilla by running these commands:
  export SERVICE_PORTS=$(kubectl get svc --namespace $namespace $service_name --template "{{ range .spec.ports }}{{.port}} {{ end }}")
  eval "kubectl port-forward --namespace $namespace service/$service_name $SERVICE_PORTS"