Add alerta username and password to models

Change-Id: I422ec5d59fe1414abfa2f2e2f25421afcc9f0626
PROD-related: PROD-21265
diff --git a/classes/cluster/sl-k8s-calico/stacklight/init.yml b/classes/cluster/sl-k8s-calico/stacklight/init.yml
index 3910a1a..08777c5 100644
--- a/classes/cluster/sl-k8s-calico/stacklight/init.yml
+++ b/classes/cluster/sl-k8s-calico/stacklight/init.yml
@@ -16,6 +16,8 @@
     # Prometheus
     prometheus_control_address: ${_param:stacklight_monitor_address}
     stacklight_log_address: ${_param:stacklight_monitor_address}
+    alerta_admin_username: "admin@alerta.io"
+    alerta_admin_password: "alerta"
 
     mysql_admin_user: root
     mysql_admin_password: workshop