Address problems with KeyboardDragListener options

[jessegreenberg]

A couple of problems identified while working on #1614

• There are some option differences between KeyboardDragListener and DragListener that are making practical use of Combine DragListener and KeyboardDragListener into a single class #1614 difficult. For example modelDelta (DragListener) is called vectorDelta in KeyboardDragListener.
• KeyboardDragListener doesn't support translateNode.
• The delta provided by KeyboardDragListener is not available if you don't provide a positionProperty and use drag callback directly instead.

Lets clean these things up and make the API for DragListener and KeyboardDragListener more similar. This will make it easier to use RichDragListener.

[jessegreenberg]

The fields and options are better aligned. I also made it more clear how deltas are applied in the drag action and fixed how translateNode works.