Add cluster_labels and annotations to logical backup CronJob and Jobs (#3085)

* Add cluster_labels and annotations to logical backup CronJob and Jobs

When using the logical backup feature, the CronJob and its created Jobs
were missing the cluster_labels and annotations that are applied to
other cluster resources. This made it difficult to filter or identify
backup jobs using the same labels as other cluster components.

Changes:
- Added ObjectMeta with labels and annotations to JobTemplateSpec
- Updated CronJob ObjectMeta to use the merged labels (including
  'application: spilo-logical-backup')
- Updated tests to expect the new labels

pkg/cluster/util.go

@@ -167,6 +167,14 @@ func metaAnnotationsPatch(annotations map[string]string) ([]byte, error) {
 	}{&meta})
 }
 
+func metaLabelsPatch(labels map[string]string) ([]byte, error) {
+	var meta metav1.ObjectMeta
+	meta.Labels = labels
+	return json.Marshal(struct {
+		ObjMeta interface{} `json:"metadata"`
+	}{&meta})
+}
+
 func (c *Cluster) logPDBChanges(old, new *policyv1.PodDisruptionBudget, isUpdate bool, reason string) {
 	if isUpdate {
 		c.logger.Infof("pod disruption budget %q has been changed", util.NameFromMeta(old.ObjectMeta))