Add alerta username and password to models

Change-Id: I422ec5d59fe1414abfa2f2e2f25421afcc9f0626
PROD-related: PROD-21265
diff --git a/classes/cluster/sl-k8s-contrail/stacklight/init.yml b/classes/cluster/sl-k8s-contrail/stacklight/init.yml
index c8ed2df..cb3d5bd 100644
--- a/classes/cluster/sl-k8s-contrail/stacklight/init.yml
+++ b/classes/cluster/sl-k8s-contrail/stacklight/init.yml
@@ -17,7 +17,8 @@
 
     # Prometheus
     prometheus_control_address: ${_param:stacklight_monitor_address}
-
+    alerta_admin_username: "admin@alerta.io"
+    alerta_admin_password: "alerta"
     mysql_admin_user: root
     mysql_admin_password: workshop