<!--IssueSummary start--> <details> <summary> Everyone can contribute. [Help move this issue forward](https://handbook.gitlab.com/handbook/marketing/developer-relations/contributor-success/community-contributors-workflows/#contributor-links) while earning points, leveling up and collecting rewards. </summary> - [Work on this issue](https://contributors.gitlab.com/manage-issue?action=work&projectId=278964&issueIid=589734) - [Close this issue](https://contributors.gitlab.com/manage-issue?action=close&projectId=278964&issueIid=589734) </details> <!--IssueSummary end--> Create base service for v2 approval rules. Requirements: - Shared authorisation helper (`can_update_approvers?`) - ServiceResponse helpers (error/success) - Accessors (merge_request, current_user, params, project) This will be used by the new v2 Create, Update, and Destroy services. Reference: [POC implementation](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/222865) in `poc/v2-approval-rules-complete` branch