Add append and prepend to scramble.extensions

[LeTamanoir]

Scramble is such an awesome library, congrats for all the work that is going into it 🙏

I was facing an "issue" with the RequestBodyExtension that was unable to extract the parameters of some requests.
Sometimes some of my controller / request logic can rely on custom injected parameters:

class Controller {
   public function __construct() {
      app()->bind(MyCustomClass::class, [...]);
   }

   public function index(Request $request) {
      return 'ok';
   }
}

class Request extends FormRequest {
   public function rules() {
      return [
         'toto' => app(MyCustomClass::class)->getSomeRule()
      ];
   }
}

But as scramble does not call the controller's __construct (which I guess is a good thing 🤔) the MyCustomClass is not bound to the app and thus the rule can't be resolved.

For this to work in scramble I would need to create a custom operation extension that does what is done inside the controller's __construct method and it should be executed before the others default extensions:

return array_merge(
   $prependOperationExtensions,
   [
      RequestEssentialsExtension::class,
      RequestBodyExtension::class,
      ErrorResponsesExtension::class,
      ResponseExtension::class,
      DeprecationExtension::class,
   ],
   $appendOperationExtensions
);

Maybe the extensions config could take 2 params: append and prepend to inject the middleware accordingly ?

[romalytvynenko]

@LeTamanoir that totally makes sense! I'm working on something exactly like this. Will comment here once ready

[romalytvynenko]

@LeTamanoir you can now do this in 0.12.x!

https://scramble.dedoc.co/developers/customize-openapi-documents#operation-transformers