Move to Symfony Flex

The structure changed completely.
Bundles are gone. Everything is flatten in the folder `src`.
I separated import & api controllers to avoid _pollution_ in the main controller folder.

config/packages/prod/doctrine.yaml

@@ -0,0 +1,18 @@
+doctrine:
+    orm:
+        auto_generate_proxy_classes: false
+        proxy_dir: '%kernel.build_dir%/doctrine/orm/Proxies'
+        query_cache_driver:
+            type: pool
+            pool: doctrine.system_cache_pool
+        result_cache_driver:
+            type: pool
+            pool: doctrine.result_cache_pool
+
+framework:
+    cache:
+        pools:
+            doctrine.result_cache_pool:
+                adapter: cache.app
+            doctrine.system_cache_pool:
+                adapter: cache.system

config/packages/prod/jsm_serializer.yaml

@@ -0,0 +1,6 @@
+jms_serializer:
+    visitors:
+        json_serialization:
+            options:
+                - JSON_UNESCAPED_SLASHES
+                - JSON_PRESERVE_ZERO_FRACTION

config/packages/prod/monolog.yaml

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+monolog:
+    handlers:
+        main:
+            type: fingers_crossed
+            action_level: error
+            handler: nested
+            excluded_http_codes: [404, 405]
+            buffer_size: 50 # How many messages should be saved? Prevent memory leaks
+        nested:
+            type: stream
+            path: php://stderr
+            level: debug
+            formatter: monolog.formatter.json
+        console:
+            type: console
+            process_psr_3_messages: false
+            channels: ["!event", "!doctrine"]
+        deprecation:
+            type: stream
+            channels: [deprecation]
+            path: php://stderr

config/packages/prod/routing.yaml

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+framework:
+    router:
+        strict_requirements: null

config/packages/prod/sentry.yaml

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+sentry:
+    dsn: '%env(SENTRY_DSN)%'
+    options:
+        excluded_exceptions:
+            - Symfony\Component\HttpKernel\Exception\NotFoundHttpException
+            - Symfony\Component\Security\Core\Exception\AccessDeniedException
+
+#    If you are using Monolog, you also need these additional configuration and services to log the errors correctly:
+#    https://docs.sentry.io/platforms/php/guides/symfony/#monolog-integration
+#    register_error_listener: false
+
+#    monolog:
+#        handlers:
+#            sentry:
+#                type: service
+#                id: Sentry\Monolog\Handler
+
+#    services:
+#        Sentry\Monolog\Handler:
+#            arguments:
+#                $hub: '@Sentry\State\HubInterface'
+#                $level: !php/const Monolog\Logger::ERROR