Support "Create Galaxy config" action properly

Scenario:

1. Open the WD.
   Current state: the scene is empty.
2. Select "Actions --> Create Galaxy tool config".
   Current state: an error message box appears:

      Workflow does not contain any parameter aliases.
      

3. Add a few elements to the scene (also create a few parameter aliases).
4. Select "Actions --> Create Galaxy tool config".
   Current state: nothing happens.

Specify the behavior of this action: implement it and create a documentation for it.