Move Usage below Configuration

* https://github.com/WideEyeLabs/cookbook-gitlabhq/pull/35#discussion_r6421853
Consistent Syntax

* https://github.com/WideEyeLabs/cookbook-gitlabhq/pull/35#discussion_r6421985
Use Stable Branches instead of Versions
Move gitlab-specific backup-attributes
Make sure we have a trailing slash

* https://github.com/WideEyeLabs/cookbook-gitlabhq/pull/35#r6432288