feat #  prototype for section refresh animation

implementation of the section refresh animation
In my opinion, there is no need to create the `this._animation` property, as it is easy to recompute it, and not storing it would allow to change the animation config property directly (cf my previous remark).
Moreover, the object stored in `this._animation` does not match the structure expected by `aria.utils.css.Animations`, so I would prefer storing each value of this object in a variable for better minification (whose name can be shortened), and move the whole content of this method to `animateRefresh`.