Stunner - Improve the keyboard integration support

Candidate hotkey's to add are:

• Move shape up/down/right/left
  • Using the arrow keys the user should be able to change the location for a shape
  • Consider when using Shift/Ctrl while pressing some arrow key, it should change location as well but using more "distance"
  • Consider when multiple shapes are selected, not just a single one -> so all selected shapes have to be re-positioned once using some arrow key
  • Consider canvas bounds constraints -> moving shapes using the arrows cannot exceed the canvas bounds