Automatic merge from submit-queue (batch tested with PRs 45913, 46065, 46352, 46363, 46373)

Update audit API with missing pieces

Follow-up to https://github.com/kubernetes/kubernetes/pull/45315 to resolve pending decisions & issues, including:

- Audit ID format
- Identifying audit event "stage"
- Request/Response object format (resolve conversion issue)
- Add a subresource field to the `ObjectReference`

For https://github.com/kubernetes/features/issues/22

~~TODO: Add generated code once we've reached consensus on the types.~~

/cc @deads2k @ihmccreery @sttts @soltysh @ericchiang