Move terraform and kubernetes folder to be under proxy (#127)

* Move terraform and kubernetes folder to be under proxy

There is no reason for them to be under proxy/src/... any more now that
we have a Gradle-idiomatic folder structure.

proxy/terraform/modules/gke/cluster.tf

@@ -0,0 +1,40 @@
+locals {
+  proxy_cluster_zone = "${lookup(var.proxy_cluster_zones, var.proxy_cluster_region)}"
+}
+
+resource "google_container_cluster" "proxy_cluster" {
+  name = "proxy-cluster-${var.proxy_cluster_region}"
+  zone = "${local.proxy_cluster_zone}"
+
+  timeouts {
+    update = "30m"
+  }
+
+  node_pool {
+    name               = "proxy-node-pool"
+    initial_node_count = 1
+
+    node_config {
+      tags = [
+        "proxy-cluster",
+      ]
+
+      service_account = "${var.proxy_service_account_email}"
+
+      oauth_scopes = [
+        "https://www.googleapis.com/auth/cloud-platform",
+        "https://www.googleapis.com/auth/userinfo.email",
+      ]
+    }
+
+    autoscaling {
+      max_node_count = 5
+      min_node_count = 1
+    }
+
+    management {
+      auto_repair  = "true"
+      auto_upgrade = "true"
+    }
+  }
+}