title: Delayed Job: Configure run_at and max_attempts for a specific job
body: <p>I need to overwrite the <code>Delayed::Worker.max_attempts</code> for one specific job, which I want to retry a lot of times. Also, I don't want the next scheduled time to be determined exponentially (From the docs: 5 seconds + N ** 4, where N is the number of retries).</p>
  
  <p>I don't want to overwrite the <code>Delayed::Worker</code> settings, and affect other jobs.</p>
  
  <p>My job is already a custom job (I handle errors in a certain way), so that might be helpful. Any pointers on how to do this?</p>