title: CELERY_IMPORTS, CELERY_RESULT_BACKEND deprecated. How to use alternative?
body: <p>when setting celery's config like this in celery 5.0.2</p>
  <pre><code>CELERY_BROKER_URL='amqp://localhost',
  CELERY_IMPORTS=('my_tasks', 'callbacks'),
  CELERY_RESULT_BACKEND='rpc://')
  </code></pre>
  <p>deprecated warnings about <code>CELERY_IMPORTS</code> and <code>CELERY_RESULT_BACKEND</code> to use</p>
  <p><code>alternative=f'Use the {_TO_NEW_KEY[setting]} instead')</code> in version 6.0.0 appear.</p>
  <p>Could anyone explain how this is meant?</p>