Add private domains to cf-for-k8s

add-private-domains.yml

#@ load("@ytt:overlay", "overlay")
#@ load("@ytt:data", "data")

#@overlay/match by=overlay.subset({"kind": "Gateway", "metadata": {"name": "istio-ingressgateway"}})
---
spec:
  servers:
  #@overlay/match by=overlay.subset({"port": {"name": "https-workloads" }})
  - hosts:
    #@ for/end private_domain in data.values.private_domains:
    #@overlay/append
    - #@ 'cf-workloads/*.' + private_domain
    #@overlay/append
    - #@ 'cf-workloads/' + private_domain

values.yml

#@data/values
#@overlay/match-child-defaults missing_ok=True
--- 

.....
private_domains:
- "mydomain.com"
...