Allow to setup notification callback for all abilities

[davydovanton]

Let's try to create only after_call_callback for broadcasting notifications for any frameworks:

abilities = Kan::Application.new(
  post: Post::Abilities.new(after_call_callback: -> (ability_name, payload) { ... }),
  comment: Comments::Abilities.new
)

abilities['post.read'].call(current_user, post) # => true
abilities['post.delete'].call(current_user, post) # => false
abilities['comment.delete'].call(current_user, post) # => false