Migrating to the new gitlab runner registration workflow

There is a new system called runner authentication tokens rather than runner registration tokens for GitLab runners. For now, we have re-enabled the old workflow, we should move to the new one prior to the release of GitLab 18.0.

Useful resources:

• https://docs.gitlab.com/ee/ci/runners/new_creation_workflow.html
• https://docs.gitlab.com/runner/register/
• https://docs.gitlab.com/charts/charts/gitlab/gitlab-runner/