Switch FAST networking stages to network policies for Google domains (#1352)

* peering stage implementation

* vpn stage implementation

* tfdoc

* tests

* add most supported google domains

* align all net stages

* add support for factory to DNS response policy module

* use dns policy factory in network stages

* boilerplate

modules/dns-response-policy/variables.tf

@@ -64,3 +64,9 @@ variable "rules" {
   default  = {}
   nullable = false
 }
+
+variable "rules_file" {
+  description = "Optional data file in YAML format listing rules that will be combined with those passed in via the `rules` variable."
+  type        = string
+  default     = null
+}