Update terraform files and instructions (#1402)

* Update terraform files and instructions

Update proxy terraform files based on current best practices and allow
exclusion of forwarding rules for HTTP endpoints.  Specifically:
-   Add a "public_web_whois" input to allow disabling the public HTTP
    whois forwarding.
-   Add "description" fields to all variables.
-   Move outputs of the top-level module into "outputs.tf".
-   Auto-reformat using hclfmt.

proxy/terraform/example_config.tf

@@ -11,21 +11,8 @@ module "proxy" {
   proxy_project_name       = "YOUR_PROXY_PROJECT"
   gcr_project_name         = "YOUR_GCR_PROJECT"
   proxy_domain_name        = "YOUR_PROXY_DOMAIN"
-  proxy_certificate_bucket = "YOU_CERTIFICATE_BUCKET"
-}
+  proxy_certificate_bucket = "YOUR_CERTIFICATE_BUCKET"
 
-output "proxy_service_account" {
-  value = module.proxy.proxy_service_account
-}
-
-output "proxy_name_servers" {
-  value = module.proxy.proxy_name_servers
-}
-
-output "proxy_instance_groups" {
-  value = module.proxy.proxy_instance_groups
-}
-
-output "proxy_ip_addresses" {
-  value = module.proxy.proxy_ip_addresses
+  # Uncomment to disable forwarding of whois HTTP interfaces.
+  # public_web_whois         = 0
 }