Ensure the gitlab-cookbooks don't dirty omnibus cache too soon

Part of #4662 (closed)

Due to how omnibus does build ordering, it builds two lists. A list of software that others depend on, then a list of project dependencies. Then combines the two, with the first lists' entries now all coming before the seconds.

The gitlab-cookbooks was being added to the first group because the chef-acme software relies on it. And software that ended up in the later group are typically our large services.