[CICD] Update 'gitlab-ci' revision to the latest available version

* The 'scarthgap-dev' branch was misaligned from the CI state of the art because the integration of 'gitlab-ci' modification is working only on 'scarthgap' branches.

* Change submodule paths to relative paths as per CI requirement (see https://git.seco.com/clea-os/infrastructure/gitlab-ci/-/blob/master/docs/add-new-project-to-pipeline.md?ref_type=heads#add-submodule-gitlab-ci)