Start rewrite custom rest example

Author: adriendupuis

code_samples/api/rest_api/config/services.yaml

@@ -41,12 +41,7 @@ services:
         autoconfigure: true
         tags: [ 'controller.service_arguments' ]
 
-    App\Rest\ValueObjectVisitor\Greeting:
-        parent: Ibexa\Contracts\Rest\Output\ValueObjectVisitor
-        tags:
-            - { name: ibexa.rest.output.value_object.visitor, type: App\Rest\Values\Greeting }
 
-    App\Rest\InputParser\GreetingInput:
-        parent: Ibexa\Rest\Server\Common\Parser
-        tags:
-            - { name: ibexa.rest.input.parser, mediaType: application/vnd.ibexa.api.GreetingInput }
+    App\Rest\Serializer\:
+        resource: '../src/Rest/Serializer/'
+        tags: ['ibexa.rest.serializer.normalizer']