Represent knp menu by yml config

[eddiejaoude]

Example:

// ...
   $menu->addChild('nav.home', array('route' => 'quickstart_app_homepage'));
   $menu->addChild('nav.register', array('route' => 'fos_user_registration_register'));
   $menu->addChild('nav.login', array('route' => 'fos_user_security_login'));
// ...

Could be expressed in yml config...

# ...
menu:
   main:
      nav.home:
         route: quickstart_app_homepage
      nav.register:
         route: fos_user_registration_register
      nav.login:
         route: fos_user_security_login
# ...