Add gizmos for shape editing for collider shapes

[mrDIMAS]

At this point, collider shapes can be edited only via Inspector and this could be quite time consuming. Having a gizmo that allows editing shapes directly in the scene preview would significantly speed things up.

[mrDIMAS]

This is done, now a new interaction mode button (with triangle icon) appears on the toolbar when selecting a collider and by activating this mode you can edit collider shape by dragging respective handles.