setting $Local:DB::NO_LOG_QUERIES true was preventing sql trace output in QueryLogger::log_query so moved it to QueryLogger to take effect on dispatcher log() command; new Utils::datetime_to_string method + test file
Fix consequence of previous update to support multiple worksheets default worksheet 'sheet1' no longer set becuase worksheet() method not called now have to set manually inside _write_xlsx_row() if ->worksheet_name() not set in calling script
