* @param string $key The configuration key to query
* @param mixed $default_value optional, The value to return if key is not set (default: null)
* @param boolean $refresh optional, If true the config is loaded from the db and not from the cache (default: false)
*
* @return mixed Stored value or null if it does not exist
*/
* @param string $key The configuration key to query
* @param mixed $default_value optional, The value to return if key is not set (default: null)
* @param boolean $refresh optional, If true the config is loaded from the db and not from the cache (default: false)
*
* @return mixed Stored value or null if it does not exist
*/