Support both Drupal 8 and Composer 1/2

[hkirsman]

So the issue is that you can't install Code Quality with Drupal 8 and Composer 2. The dependencies just don't match.

You can try it with this small project I just created https://github.com/hkirsman/drupal8-composer2-code-quality See readme. Maybe you can make it work?

I've created 1-x branch from the latest head. From there I downgraded GrumPHP to 0.18.1 because there they added Composer 2 support, it works with our Code Quality and still doesn't have the conflicting dependencies.

PR ready to be tested