feat: revoke supabase_*_admin from postgres

Prevents Auth and Storage schemas & migrations from being modified

Author: soedirgo

migrations/db/migrations/20250421084701_revoke_supabase_storage_admin_from_postgres.sql

@@ -0,0 +1,10 @@
+-- migrate:up
+revoke supabase_storage_admin from postgres;
+revoke create on schema storage from postgres;
+revoke all on storage.migrations from anon, authenticated, service_role, postgres;
+
+revoke supabase_auth_admin from postgres;
+revoke create on schema auth from postgres;
+revoke all on auth.schema_migrations from dashboard_user, postgres;
+
+-- migrate:down