Support new PAT feature in GitLab Shell

What does this MR do?

Support new PAT feature in GitLab Shell

Contributes to #5763 (closed)

New configuration options were added to gitlab-shell: gitlab-org/gitlab-shell!1141 (merged)

Allow to configure them via helm charts.

Related issues

Support new PAT feature in GitLab Shell (#5763 - closed)

Author checklist

For general guidance, please follow our Contributing guide.

Required

For anything in this list which will not be completed, please provide a reason in the MR discussion.

• Merge Request Title and Description are up to date, accurate, and descriptive.
• MR targeting the appropriate branch.
• MR has a green pipeline.
• Documentation created/updated.
• Tests added/updated, and test plan for scenarios not covered by automated tests.
• Equivalent MR/issue for omnibus-gitlab opened. (Yes: Support PAT configuration for gitlab-shell (gitlab-org/omnibus-gitlab!7887 - merged))

Reviewers checklist

• MR has a green pipeline on https://gitlab.com/gitlab-org/charts/gitlab.
• Consider downstream impact to the Operator, as per evaluating impact from changes to GitLab Chart.