Refactor the onprem module (#55)

* move onprem to cos-container

* compute-vm: fix external addresses output

* folders-unit: update README

* update onprem module, add new fields to cos-container test instance

* coredns: process corefile as a template

* onprem: fixes

* modules/cos-container: rename to cloud-config-container infra/onprem: remove test output

* Update README.md

* update CHANGELOG for v1.1.0

* fix cloud config modules tests

* Update main.tf

* add container nginx module

modules/compute-vm/outputs.tf

@@ -20,7 +20,7 @@ output "external_ips" {
     var.network_interfaces[0].nat
     ? [
       for name, instance in google_compute_instance.default :
-      instance.network_interface.0.network_ip
+      try(instance.network_interface.0.access_config.0.nat_ip, null)
     ]
     : []
   )