title: Django query, annotate latest childs value
body: <p>Is it possible to annotate value of last child? There is model  StoreItem, that has relation has many to model Movement: </p>
  
  <pre><code>StoreItem.objects.last().movements.last().total_count # =&gt; 32
  </code></pre>
  
  <p>I need something like:</p>
  
  <pre><code>StoreItem.objects.annotate(total_count_of_last_movement=...??...)
  </code></pre>
  
  <p>Thank you! </p>