Current rendering listeners are quite limited as they are not able influence rendering engine in any way. We need to be able return some sort of status from listeners so rendering engine could react on that.

1. Make info.magnolia.rendering.context.RenderingListener deprecated in favour of AbstractRenderingListener:
   Nonparametric constructor by be able instantiate by N2B.
   String AbstractRenderingListener.init() method (any logic from RederingListener s constructors should go there).
   String AbstractRenderingListener.before().
   String AbstractRenderingListener.after().
2. The configuration of listeners should be moved from info.magnolia.rendering.renderer.registry.RendererRegistry to RenderingEngine as it doesn't belong there.
3. Handle results of rendering listeners in RenderingEngine/RenderingFilter