Auditing self-hosted instance-level configuration changes

For audit purposes, GitLab stores configuration events as audit logs. For self hosted, we need to audit the following events:

• Enable self-hosted models workflowin review Logs audit events for self-hosted model terms a... (!165480 - merged)
• Delete self-hosted model workflowin review Audit deletion of self-hosted models (!165321 - merged)
• Create new self-hosted model workflowin review Audit event for model creation (!165303 - merged)
• Update model for a feature workflowin review Auditing self-hosted instance-level configurati... (!165489 - merged)

Contributor docs on audit events: https://docs.gitlab.com/ee/development/audit_event_guide/ User docs on audit events: https://docs.gitlab.com/ee/user/compliance/audit_events.html