[export] Fixed: the scope aggregator (accompanying course) group by

period's scope (and the label didn't show this)

+ extract ScopeRepository and create ScopeRepositoryInterface

src/Bundle/ChillPersonBundle/Export/Aggregator/AccompanyingCourseAggregators/ScopeAggregator.php

@@ -83,6 +83,6 @@ final class ScopeAggregator implements AggregatorInterface
 
     public function getTitle(): string
     {
-        return 'Group by user scope';
+        return 'Group course by scope';
     }
 }