dbquery: remove run_sql_cached() and its clients

• Remove run_sql_cached() and update all its clients to use run_sql(). The function was inactivated since a9e7e16d35509e3b2dfc1e87183fd537f8a7488c due to performance reasons anyway. Moreover, it would not work well in load-balanced multi-node environment due to worker node syncing. (Proper DataCachers should be introduced for every client if we want to retain this functionality.)