fix: run huey in background (again)

Author: StefanFl

docker/backend/dev/django/entrypoint

@@ -41,7 +41,7 @@ EOD
 fi
 
 python manage.py flush_huey_inflight
-python manage.py run_huey --flush-locks
+python manage.py run_huey --flush-locks &
 
 python manage.py register_parsers
 python manage.py initial_license_load

docker/backend/prod/django/entrypoint

@@ -47,7 +47,7 @@ fi
 python /app/manage.py collectstatic --noinput
 
 python manage.py flush_huey_inflight
-python manage.py run_huey --flush-locks
+python manage.py run_huey --flush-locks &
 
 python manage.py register_parsers
 python manage.py initial_license_load