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.

查看之前的 issue stackable-cockpit#333，以了解第一个解决方案和剩余的拟议方案。找出 demo-install 的入口点和相关的 Kubernetes Jobs，然后添加用于区分幂等 job 与应忽略 job 的 labels；完成标准是 demo 安装可以在更少手动操作的情况下重新运行和升级。