title: Specflow StepArgumentTransformation: move to separate file
body: <p>I am trying to place my <code>StepArgumentTransformations</code> into a "Utility File" so that multiple StepDefinitions can use them.
  Unfortunately it looks like they need to be in the same StepDefinition class where they are used.</p>
  
  <p>Is there a way so that specflow searches them in the whole project? (like it does for the step bindings)
  I don't want to copy the transformations into each StepDefinition class where I want to use them.</p>