Add KUBERNETES_CLUSTER_DOMAIN only if set (removed default) (#449)

* add KUBERNETES_CLUSTER_DOMAIN only if set (removed default)

* fix whitespace

Author: maltesander

template/deploy/helm/[[operator]]/templates/deployment.yaml.j2

@@ -48,8 +48,10 @@ spec:
               valueFrom:
                 fieldRef:
                   fieldPath: metadata.annotations['internal.stackable.tech/image']
+            {{- if .Values.kubernetesClusterDomain }}
             - name: KUBERNETES_CLUSTER_DOMAIN
-              value: {{ .Values.kubernetesClusterDomain | default "cluster.local" | quote }}
+              value: {{ .Values.kubernetesClusterDomain | quote }}
+            {{- end }}
 {[% if operator.product_string in ['kafka'] %}]
             - name: KAFKA_BROKER_CLUSTERROLE
               value: {{ include "operator.fullname" . }}-kafka-broker-clusterrole