[5.x] Add horizon:forget command to delete a failed job

[paras-malhotra]

Currently, there's no way to delete a failed job from both Redis and the database. The queue:forget command in the framework simply deletes the job from the database but the Horizon dashboard still shows the job as failed.

This PR provides a clean way for users using Horizon to delete failed jobs.

[driesvints]

Wondering if we can make this a bit more generic as a ForgetCommand that can delete any job but has flags like --failed to specifically delete failed jobs. Does that even makes sense?

[paras-malhotra]

@driesvints I wanted to make it mirror the queue:forget like we have horizon:clear and queue:clear.

Also, there's no way to delete a pending job using the Framework. The delete function on the Job class just deletes reserved jobs and doesn't work for pending jobs. I guess this hasn't been added to the framework as it would be very inefficient for queues like Redis that either need a full scan operation or would need to reconstruct the original job json payload.

[driesvints]

@paras-malhotra gotcha. Makes sense 👍