Implement behavioral logic

[thomaspeugeot]

Steps:

• Connect the Rect to update to Rect

In the behavior function

• Add ShowHorizontalHandles and allow Handles to appears only if true
• Add CanHaveHorizontalHandles and set ShowHorizontalHandles to true if Selected and CanHaveHorizontalHandles
• Add CanBeMovedHorizontally
• Add CanBeMovedVertically
• Allow a control inversion via a RectUpdated(stagedRect, backRepoRect *gongsvg_models.Rect)