title: Javers compare String null and "" empty String
body: <p>Is it possible to configure Javers so that when comparing two objects which have a String property that has the value null or "" (empty) String it will not find any difference. Basically treat null and "" empty string the same.
  For example:</p>
  
  <pre><code>Class Phone 
  {
      String phoneNumber;
      Phone(phoneNumber)
      {
           this.phoneNumber = phoneNumber;
      }
  
  }
  Phone phoneNumber = new PhoneNumber("");
  Phone phoneNumber1 = new PhoneNumber(null);
  </code></pre>
  
  <p>I would like that when these 2 objects will be compared by Javers, it will show no difference.</p>