QAFE-969 As QAFE developer I want to execute an event with "openwindow"
built-in on the client-side when a button is clicked so that I can
execute "openwindow" without server-side round-trip.
- Moved OpenWindow to client side
- refactored the way opening window is handled
- fixed numerous bugs/unclarities that arised on server side code
- added properties to OpenWindowGVO
- added assembler to convert OpenWindow model to OpenWindowGVO