Add terraform deployment method to contrib/examples (#1559)

Co-authored-by: Mike Joseph <mike@Mikes-MacBook-Pro-5618.local>

contrib/examples/terraform/cert-manager.tf

@@ -0,0 +1,27 @@
+# cert-manager must be deployed or included via the deployment process
+
+resource "kubernetes_namespace" "cm" {
+  metadata {
+    name = "cert-manager"
+  }
+}
+
+resource "helm_release" "cm" {
+  count            = var.actions_runner_controller
+  name             = "cm"
+  namespace        = kubernetes_namespace.cm.metadata[0].name
+  create_namespace = true
+  chart            = "cert-manager"
+  repository       = "https://charts.jetstack.io"
+  version          = "v1.8.0"
+  values = [<<EOF
+    global:
+      podSecurityPolicy:
+        enabled: true
+        useAppArmor: true
+    prometheus:
+      enabled: false
+    installCRDs: true
+  EOF
+  ]
+}