Add RemoveOldAuditCronJob to clean up outdated audit trails

- Introduced `RemoveOldAuditCronJob` class implementing `CronJobInterface` to delete old audit trails based on configured retention period.
- Added `deleteBefore` method to `AuditTrailRepository` to handle removal of records older than the specified date.
- Created `RemoveOldAuditCronJobTest` to ensure correct functionality for job execution and canRun logic.
- Updated DI configuration to include the `delete_after` parameter for audit trail retention settings.

src/Bundle/ChillMainBundle/DependencyInjection/Configuration.php

@@ -325,6 +325,12 @@ class Configuration implements ConfigurationInterface
             ->end()
             ->end();
 
+        $rootNode->children()
+            ->arrayNode('audit_trail')->addDefaultsIfNotSet()->children()
+            ->scalarNode('delete_after')->cannotBeEmpty()->defaultValue('P6M')->info('The duration (a valid interval) before deleting the audit trail. Will be run by a cronjob.')->end()
+            ->end()
+            ->end();
+
         return $treeBuilder;
     }
 }