Down-tier admin PAT API features to Core

Problem to solve

Admins need better PAT enforcement capability.

We introduced API endpoints that allow GitLab Ultimate admin users to read and revoke PAT credentials via the API. However, as explained in the epic, GitLab Core admin users are still in need of this functionality.

Proposal

• Move the admin-only API functionality for PATs to GitLab Core per &4110 (comment 422306309)
• Make these API features available to non-admin users in GitLab Core, who should be able to list and revoke their own PATs