Add support for paratest about silverstripe-framework

[emteknetnz]

Related https://github.com/silverstripeltd/product-issues/issues/689 (private repo)

[beerbohmdo]

More directories which must be seeded 🙈

if ($token = getenv('TEST_TOKEN')) {
    Requirements::backend()->setCombinedFilesFolder('_combinedfiles' . $token);
    Config::modify()->set(TinyMCECombinedGenerator::class, 'filename_base', '_tinymce' . $token . '/tinymce-{name}-{hash}.js');
}

But this can be set inside a _config.php