Fix MariaDB operator deployment namespace issue

- Remove namespace from kustomization.yaml (was putting Apps in wrong namespace)
  - Change destination to argocd namespace (Application resources must be there)
  - Add labels for tracking parent app

mariadb-operator/operator-helm.yaml

@@ -3,6 +3,8 @@ kind: Application
 metadata:
   name: mariadb-operator
   namespace: argocd
+  labels:
+    app.kubernetes.io/instance: mariadb-operator-install
 spec:
   destination:
     namespace: mariadb-system