Retrieve audit events via API: MVC
## Problem to solve
Organizations need assurance that users of GitLab are in compliance with policies they've set on the instance. Currently, instances use application and [audit logs](https://docs.gitlab.com/ee/administration/audit_events) to solve for this need; however, neither are available through an API. This makes manual exploration the primary method for investigation, and GitLab should enable proactive monitoring of audit events.
## Proposal
* Create an API endpoint for fetching audit events.
* The endpoint's response should be all relevant audit events that match the query in the get request.
* Return all relevant events for a group, project, user, or time range.
## References
Zendesk issue: https://gitlab.zendesk.com/agent/tickets/13199
GitHub: https://help.github.com/en/articles/reviewing-the-audit-log-for-your-organization#using-the-audit-log-api
issue