Validate shortcode service configurations (Case 173693)

[MalteWunsch]

I've screwed up a shortcode configuration by passing a positional parameter to the EmbeddedShortcodeHandler like this:

    webfactory.shortcode.x:
        parent: 'webfactory.shortcode.embed_inline_for_shortcode_handler'
        class: 'Webfactory\ShortcodeBundle\Handler\EmbeddedShortcodeHandler'
        arguments:
            - 'My\ShortcodeController::myAction'
        tags: [...]

which should have been a named parameter:

        arguments:
            $controllerName: 'EuroInformationen\Bundle\KrankenkassenBundle\Wechselservice\ShortcodeController::linkZuWechselFormularAction'

I wish we would throw an exception in this case (and similar cases).