Use terraform to config GCP proxy setup

With terraform (https://terraform.io) we can convert most of the infrastructure setup into code. This simplifies setting up a new proxy as well as providing reproducibility in the setup, eliminating human errors as much as possible.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=190634711

java/google/registry/proxy/terraform/modules/input.tf

@@ -0,0 +1,31 @@
+# GCP project in which the proxy runs.
+variable "proxy_project_name" {}
+
+# GCP project in which Nomulus runs.
+variable "nomulus_project_name" {}
+
+# GCP project from which the proxy image is pulled.
+variable "gcr_project_name" {}
+
+# The base domain name of the proxy, without the whois. or epp. part.
+variable "proxy_domain_name" {}
+
+# Cloud KMS keyring name
+variable "proxy_key_ring" {
+  default = "proxy-key-ring"
+}
+
+# Cloud KMS key name
+variable "proxy_key" {
+  default = "proxy-key"
+}
+
+# Node ports exposed by the proxy.
+variable "proxy_ports" {
+  type = "map"
+  default = {
+    health_check = 30000
+    whois = 30001
+    epp = 30002
+  }
+}