Added gcp terraform support (#6974)

* Added gcp terraform support

* Added http/https firewall rule

* Ignoring lifecycle changes for attached disks on the google_compute_instance

contrib/terraform/gcp/modules/kubernetes-cluster/variables.tf

@@ -0,0 +1,54 @@
+variable "region" {
+  type = string
+}
+
+variable "prefix" {}
+
+variable "machines" {
+  type = map(object({
+    node_type = string
+    size      = string
+    zone      = string
+    additional_disks = map(object({
+      size = number
+    }))
+    boot_disk = object({
+      image_name = string
+      size = number
+    })
+  }))
+}
+
+variable "master_sa_email" {
+  type = string
+}
+
+variable "master_sa_scopes" {
+  type = list(string)
+}
+
+variable "worker_sa_email" {
+  type = string
+}
+
+variable "worker_sa_scopes" {
+  type = list(string)
+}
+
+variable "ssh_pub_key" {}
+
+variable "ssh_whitelist" {
+  type = list(string)
+}
+
+variable "api_server_whitelist" {
+  type = list(string)
+}
+
+variable "nodeport_whitelist" {
+  type = list(string)
+}
+
+variable "private_network_cidr" {
+  default = "10.0.10.0/24"
+}