Swap base audit_events table with partitioned copy

As a final step to the partitioning migration of audit_events, the current non-partitioned table and the partitioned copy will need to be swapped. There may be some complexities to this, since the schema varies slightly between the two tables. The largest difference that may prove to be an issue is the composite primary key of (id, created_at) in the partitioned table.

As part of this issue:

1. Develop a plan to swap tables with minimal application impact
2. Implement any changes to the application (AuditEvent model) required to support the partitioned schema
3. Implement migration logic to be able to swap the tables in the production environment, including:
   1. recreating secondary indexes on the partitioned table
   2. move the sequence used for id generation from the original table to the partitioned table (also be sure to update the sequence owner to the new column)