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/test/web_profiler.yaml

@@ -0,0 +1,6 @@
+web_profiler:
+    toolbar: false
+    intercept_redirects: false
+
+framework:
+    profiler: { collect: false }