RFC - Implement Failed Job Admin

It might be nice to implement a job admin panel that lists all failed jobs. This could be done by having custom middleware/listeners that push the failed jobs into a database table, and then a basic page to view said jobs. We would also need a migration for creating that table, and ideally this would be something a user could generate for use with their app vs coming built-into the queue plugin.

I think @dereuromark has an example here, though in his case it also allows viewing more info about all jobs since they are all queued to the database.

In the future, we might even be able to expose other functionality/metrics in such an admin - this might involve work upstream to get the proper interfaces exposed - but I think starting here would be good enough :)

首先阅读所引用的 dereuromark/cakephp-queue 文档和 docs/admin-backend 示例，并将其方法与此插件的队列接口进行比较。定义一个涵盖失败作业存储、migration 和用户生成的管理页面的最小首个里程碑；应在实现前就“done”的标准达成一致。