Add labels for Jobs to mark them as idempotent for stackablectl demo install

This is a follow-up issue to https://github.com/stackabletech/stackable-cockpit/issues/333. Only the first suggested solution was implemented there.

The second one states: Add labels to certain jobs that are idempotent (safe to be recreated and run again), and jobs that should be ignored (initial setup jobs, eg: for Keycloak).

This is needed for idempotent demo installations and to minimize the work a developer needs to do to upgrade demos. For more context, check the previous issue.

檢視先前的 issue stackable-cockpit#333，以了解第一個解決方案和剩餘的建議方案。找出 demo-install 的進入點和相關的 Kubernetes Jobs，然後新增用於區分具冪等性的 job 與應忽略 job 的 labels；完成的條件是 demo 安裝可以用較少的手動工作重新執行和升級。