change event type in BootstrapListenerInterface; implement more feature ...

As discussed in #6944, this PR specializes the event type accepted by the ``onBootsrap`` method from ``Zend\EventManager\EventInterface`` to ``Zend\Mvc\MvcEvent``. It make sense as the ``Zend\Mvc\MvcEvent`` has additional methods. Also add some provider interfaces in the unittests.