#7 - implement drupal-libraries-include

[h1nds1ght]

As suggested in the issue.

1) Add this to the extra section of your main composer.json:

        "drupal-libraries-include": [
            "web/modules/contrib/webform/composer.libraries.json"
        ],

Perform a composer install => Packages should be in your libraries Folder

2) Remove it again from your main composer.json

Perform a composer install => Packages should be gone

3) Some kind of test would be nice, but I couldn't get it to run with phpunit.