Refactor config and encryption files to use instance_mac_addr variable

terraform/iac/config.tf

@@ -2,4 +2,5 @@ locals {
   instance_ips = [
     "${data.contabo_instance.microk8s.ip_config[0].v4[0].ip}/32",
   ]
+  instance_mac_addr = replace(data.contabo_instance.microk8s.mac_address, ":", "_")
 }

terraform/iac/encryption.tf

@@ -1,6 +1,6 @@
 resource "scaleway_object" "encryption_key" {
   bucket = scaleway_object_bucket.infra_assets.id
-  key    = "keys/${replace(data.contabo_instance.microk8s.mac_address, ":", "_")}.key"
+  key    = "keys/${local.instance_mac_addr}.key"
 
   content_base64 = base64encode(var.encryption_key)
 }