Keyset pagination for new audit event tables

Background

Refer parent epic for more details Compliance: audit_events table changes required (&13370)

The audit events table (audit_events) was split into the following 4 tables:

• UserAuditEvent
• ProjectAuditEvent
• GroupAuditEvent
• InstanceScopeAuditEvent

Problem to solve

As part of this Cells work we have split the audit events table into four seperate tables based on the event scopes (Instance, Group, Project and User). We need to provide API to fetch audit events, for this we need a combined finder supporting keyset pagination

Proposal

Write a combined finder supporting keyset pagination.