ADO Branch policies to GitLab Merge request approval rules

Overview

As part of this Issue: #1304, working on migrating ADO branch policies to GitLab Merge Request Approvals

Tasks

• Update docs if needed (workflow, runbooks, README, migration metrics, etc.)

Acceptance Criteria

• Add changes/update the runbook for ADO
• Add changes to https://gitlab.com/gitlab-org/professional-services-automation/tools/migration/congregate/-/blob/master/customer/ado-migration-features-matrix.md
• Create a recording showing the migration features that are migrated
• Existing UTs pass locally. If you need help updating any tests, refer to our writing tests documentation