Add runner controller and runner controller tokens API to global nav

Add navigation item to global navigation

• Link to the merge request that introduced the new page: gitlab-org/gitlab!218229 (merged)
• Give the MR a descriptive title.
• Optional. Link to the review app showing the new page: https://docs.gitlab.com/review-mr-1741/api/runner_controller_tokens/ and https://docs.gitlab.com/review-mr-1741/api/runner_controllers/