Contributes to https://gitlab.com/gitlab-org/gitlab-shell/-/issues/735

**Problem**

depguard linter complains about unknown packages.

**Solution**

Add a configuration with a list of allowed packages.

- Add comments and refactor
- Update depguard configuration

Contributes to: https://gitlab.com/gitlab-org/gitlab-shell/-/issues/738

This was extracted from the gitlab-build-images file.