Add an option to not snap to anchor during `Align Target` listener response

Currently, when using Align Target in a listener, the target gets snapped to the pointer by its anchor point.
I suggest adding a checkbox that would allow for its movement to begin at a relative offset from the pointers original position at the beginning of the listener trigger.

With target not snapping to the pointer to the anchor would allow for realistic panning/dragging experience that is expected in UI/UX interactions.

I understand this isn't a trivial matter, since it has some other implications, like how to manage when object goes out of bounds of the artboard. However, relative dragging/panning is a needed thing if Rive is to be used for more complex UI element production.