feat(backend): copy cron tasks without decorators to be executed manually

backend/_cron_tasks.py

+from backend_app.models.exchange import update_denormalized_univ_major_minor
+
+from backend_app.models.university import update_denormalized_univ_field  # noqa: E402
+from external_data.management.commands.utils import FixerData, UtcData  # noqa: E402
+from base_app.management.commands.clean_user_accounts import (
+    ClearUserAccounts,
+    ClearSessions,
+)
+from stats_app.compute_stats import update_all_stats
+
+
+def update_currencies():
+    FixerData().update()
+
+
+def update_utc_ent():
+    UtcData().update()
+
+
+def update_extra_denormalization():
+    update_denormalized_univ_major_minor()
+    update_denormalized_univ_field()
+
+
+def clear_and_clean_sessions():
+    ClearUserAccounts.run()
+    ClearSessions.run()
+
+
+def update_daily_stats():
+    update_all_stats()