title: How to I call the "Read value from XML file" action from custom code?
body: <p>The title says it all - I need to refactor multiple mini-actions into a single coherent piece of custom code, and to keep the refactoring under control, I want to stick with Install4J Actions as far as possible.
  I checked the type hierarchy below <code>com.install4j.api.actions.Action</code> but found nothing XML-related.</p>
  
  <p>BTW eventually the installer will have to call the "Replace text in XML files" action as well.<br>
  I.e. I'll appreciate any hints for a general strategy to find any action, given the name shown in the "Select an installation Action" dialog or in the "Screens &amp; Actions" section of the Install4J GUI.</p>