🏭️ Refactor prepare-tf

- fix tags so that they don't contain '='
- install metrics-server only if necessary
- set a maximum size to GKE node pool
- change tags to be shorter

prepare-tf/modules/oraclecloud/outputs.tf

@@ -9,3 +9,7 @@ output "kubeconfig" {
 output "cluster_id" {
   value = oci_containerengine_cluster._.id
 }
+
+output "has_metrics_server" {
+  value = false
+}