Add k8s metallb switch parameter in k8s models

Use part of private adresses pool for metallb addresses.
By default metallb is disabled.

Change-Id: I60f62abbbf5681a91304c88560912f43802a89f2
Related-PROD: PROD-21474
diff --git a/classes/cluster/sl-k8s-calico/kubernetes/init.yml b/classes/cluster/sl-k8s-calico/kubernetes/init.yml
index c97e665..6976009 100644
--- a/classes/cluster/sl-k8s-calico/kubernetes/init.yml
+++ b/classes/cluster/sl-k8s-calico/kubernetes/init.yml
@@ -37,6 +37,7 @@
     kubernetes_criproxy_checksum: md5=115bbb0c27518db6b0b3bc8cdc5fc897
     kubernetes_externaldns_image: mirantis/external-dns:latest
     kubernetes_externaldns_provider: coredns
+    kubernetes_metallb_addresses_pool: 172.16.10.60-172.16.10.80
 
     # switches of addons
     kubernetes_helm_enabled: true
@@ -45,6 +46,7 @@
     kubernetes_virtlet_enabled: false
     kubernetes_coredns_enabled: false
     kubernetes_externaldns_enabled: false
+    kubernetes_metallb_enabled: false
 
     # addresses and hostnames
     kubernetes_internal_api_address: 10.254.0.1