Fix review apps cleanup

What does this MR do?

1. Fix the automated review apps cleanup job

• The job needed an environment declared in order to be able to communicate with the Kubernetes cluster.

1. Improve automated Review Apps cleanup

TODO:

• Port to CE: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/22375

What are the relevant issue numbers?

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/52112, https://gitlab.com/gitlab-org/gitlab-ee/issues/7657

Does this MR meet the acceptance criteria?

• [-] Changelog entry added, if necessary
• [-] Documentation created/updated
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• EE specific content should be in the top level /ee folder