Audit all project-level merge request approval settings

Release notes

Changes made to any settings under https://docs.gitlab.com/ee/user/project/merge_requests/merge_request_approvals.html#approval-settings are now audited.

Problem to solve

Cover gaps in existing audit logs when maintainers make changes to options:

• Allow overrides to approval lists per merge request
• Require new approvals when new commits are added to an MR
• Require user password for approvals

Proposal

Like !25959 (merged), cover all the remaining settings