Add metrics-server addon switcher in k8s models

Related story: https://mirantis.jira.com/browse/PROD-24599

Change-Id: I040ba6e5fa7eac552bc9c6fb7f7738440d1fc26c
diff --git a/classes/cluster/sl-k8s-calico/kubernetes/init.yml b/classes/cluster/sl-k8s-calico/kubernetes/init.yml
index da507c0..ed04ef3 100644
--- a/classes/cluster/sl-k8s-calico/kubernetes/init.yml
+++ b/classes/cluster/sl-k8s-calico/kubernetes/init.yml
@@ -47,6 +47,7 @@
     kubernetes_externaldns_enabled: false
     kubernetes_metallb_enabled: false
     kubernetes_ingressnginx_enabled: false
+    kubernetes_metrics_server_enabled: false
 
     # addresses and hostnames
     kubernetes_internal_api_address: 10.254.0.1