title: forward request to controller action
body: <p>i'd like to forward a request to a controller to some specific action without redirecting to another url.</p>
  
  <p>so, for example, the following url:<br>
  <strong>/home/peter</strong><br>
  should internally become<br>
  <strong>/home/people/peter</strong></p>
  
  <p>i know i could catch the action name ('peter') in the 'init' function, then do a Controller::redirect, but i'd like to stay on the same url, just have the request internally forwarded to the 'people' action.</p>
  
  <p>2 things to note:</p>
  
  <ul>
  <li>'peter' is a dynamic string, so i can't just hardcode a route for this</li>
  <li>any other action of the controller shall still work, so only a couple of strings should get forwared (eg. 'peter', 'ann' get forwarded to the 'people' action, whereas 'otherAction' is still callable) </li>
  </ul>
  
  <p>i already found the 'handleAction' and 'handleRequest' methods in the Controller class, but just can't imagine how make use of them for my task.</p>
  
  <p>SilverStripe version: 3.0.3</p>