* @param $config_name The config object name, for example "system.site".
* @param $key The config key, for example "page.front".
* @param $value The value to assign to the config key. Use '-' to read from STDIN.
* @param $config_name The config object name, for example "system.site".
* @param $key The config key, for example "page.front".
* @param $value The value to assign to the config key. Use '-' to read from STDIN.