Feature: #68837 - Closures for Command Line Scripts

See Issue #68837

Description

For registering new command line scripts through the CLI API ("cliKey"), it is now possible to use PHP closures instead of reference to PHP scripts.

Example usage inside ext_localconf.php:

$GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['GLOBAL']['cliKeys']['myclikey'] = array(
        function() {
                $controller = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance(\Acme\MyExtension\CommandLineTool::class);
                $controller->main();
        },
        '_CLI_lowlevel'
);