Simplify entity relationship and enforce foreign key constraints

Removed the resetStoredObject() method call from StoredObject, adjusted the storedObjectId column in the stored_object_version table to be NOT NULL, and moved the association setup of the StoredObject entity directly into the constructor in StoredObjectVersion. This ensures that every StoredObjectVersion has a valid StoredObject and maintains database integrity.

src/Bundle/ChillDocStoreBundle/Entity/StoredObject.php

@@ -346,7 +346,6 @@ class StoredObject implements Document, TrackCreationInterface
             throw new \UnexpectedValueException('This stored object does not contains this version');
         }
         $this->versions->removeElement($storedObjectVersion);
-        $storedObjectVersion->resetStoredObject();
     }
 
     /**