Add translation support

[daniel-werner]

Crete a twig function as a wrapper to Laravel translation function __()

Currently the following class can be used as a workaround:

class TwigTranslator
{
    public function __($key, $replace = [], $locale = null)
    {
        return app('translator')->getFromJson($key, $replace, $locale);
    }
}

        $twigTranlator = new TwigTranslator();
.
.
.
        $documentTemplate->addTemplateData($twigTranlator, 'trans')