import.py: Add VACUUM command

wgmaster/import.py

@@ -128,6 +128,7 @@ def main() -> None:
         if not check_foreign_keys(cnx.cursor()):
             raise RuntimeError('foreign key constraint failed')
         cnx.execute("COMMIT")
+        cnx.execute("VACUUM")
     except Exception as err:
         cnx.execute("ROLLBACK")
         raise err