title: Check file exists and create a symlink
body: <p>I want to do something like that: </p>
  
  <p>if file A exists or there is no symlink B, I want to create a symlink B -> A. </p>
  
  <p>For now I have:</p>
  
  <pre><code> B:
     file:
      - symlink:
         - target: A
      - exists:
          - name: A
  </code></pre>
  
  <p>But this is bad it checks not the thing I want. How can I achive this simple thing in salt ?</p>