Terraform release (#4613)

* Add script to build the ingress controller image using terraform

* Update terraform to 0.12.9

build/images/ingress-controller/variables.tf

@@ -0,0 +1,52 @@
+variable "access_key" {
+}
+
+variable "secret_key" {
+}
+
+variable "valid_until" {
+}
+
+variable "docker_username" {
+}
+
+variable "docker_password" {
+}
+
+variable "region" {
+  default = "us-west-2"
+}
+
+variable "cidr_vpc" {
+  description = "CIDR block for the VPC"
+  default     = "10.4.0.0/16"
+}
+
+variable "cidr_subnet" {
+  description = "CIDR block for the subnet"
+  default     = "10.4.0.0/24"
+}
+
+variable "availability_zone" {
+  description = "availability zone to create subnet"
+  default     = "us-west-2b"
+}
+
+variable "ssh_key_path" {
+  description = "Path to the SSH key"
+  default     = "~/.ssh/id_rsa"
+}
+
+variable "ssh_public_key_path" {
+  description = "Path to the public SSH key"
+  default     = "~/.ssh/id_rsa.pub"
+}
+
+variable "instance_type" {
+  description = "EC2 instance"
+  default     = "c5.18xlarge"
+}
+
+variable "project_tag" {
+  default = "kubernetes/ingress-nginx"
+}