Allow script run in silent mode

[siciarek]

It would be nice if script could run in silent mode. I use webistrano and every progress change is displayed as a separate text line. Silent parameter could be set in composer.json eg.

{
    "extra": {
        "ckeditor-quiet": true,
    }
}

And in the CKEditorScriptHandler::createCommand code

 if (isset($extra['ckeditor-quiet']) && $extra['ceditor-quiet'] === true) {
    $command .= ' --quiet';
}