Automatic merge from submit-queue (batch tested with PRs 62655, 61711, 59122, 62853, 62390). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Implemented truncating audit backend
Fixes https://github.com/kubernetes/kubernetes/issues/60432
Introduces an optional truncating backend, disabled by default, that estimates the size of audit events and truncates events/split batches based on the configuration.
/cc @sttts @tallclair @CaoShuFeng @ericchiang
```release-note
Introduce truncating audit backend that can be enabled for existing backend to limit the size of individual audit events and batches of events.
```
bf1974c83f