title: Get project directory on command symfony 3.4
body: <p>Using symfony 3.4
  In controller i can get project directory using this method : </p>
  
  <pre><code>$this-&gt;get('kernel')-&gt;getProjectDir()
  </code></pre>
  
  <p>I would like to get the project directory on command symfony (3.4) , what is the best practise to do it ?</p>
  
  <p>Thanks</p>