title: Add new icons to OpenUI5?
body: <p>We need to add new icons to OpenUI5. 
  The icons are already defined as a vector-based font. </p>
  
  <p>I know that it's possible to add the icons to the SAP standard font through a service like <a href="https://icomoon.io/" rel="nofollow">https://icomoon.io/</a>. However, I want to have to be able to maintain them outside in a separate file (so that we do not need to do redo the task when a new OpenUI5 version comes).</p>
  
  <p>Is it possible to define an additional font to use for icons?</p>