Add cors middleware

This is a basic middleware that can be registered in your app by using

    $this->registerMiddleware('CORSMiddleware');

and annotating your controller methods with @CORS 

I found this to be a very common middleware for any app that offers a RESTful API that should also be accessable from a webapp and i have duplicate classes in both notes and news

More information on that https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS

@LukasReschke @MorrisJobke @LEDFan @DeepDiver1975 @tanghus @cosenal