title: Django Admin - Add extra dialogue on field
body: <p>I would like to have an extra layer of input security on a certain field in admin, very much like the password field:</p>
  <pre><code>class MyModel(models.Model):
      very_important_field = models.CharField()
  </code></pre>
  <p>So instead of showing the input form for <code>very_important_field</code></p>
  <p>There should be a link (as with password) that leads to it's own action (like <code>/password</code>) with an own form where you would have to type in this <code>very_important_field</code> twice.</p>
  <ul>
  <li>Could you please point me to some docs how to achieve that?</li>
  </ul>
  <p>I do not need an explanation how to change the widget or how to write the proper form for this, just how to wire it in <code>admin</code> in a way that there is an extra action.</p>