Collapse / Rollup Audits

Initially we collapsed versions where if you made a version and there were no changes, you wouldn't get a new version. I think we need to do something similar (but different) for audits.

## Criteria of acceptance
If da-admin feels like an audit is needed & the users have not changed, the existing audit is "brought forward".

Below you can see an example where I've been editing a doc, and there are a ton of audits, but audits 2-14 don't provide me much value.

There's probably some nuance and details to sort out on to this: if you run into a version as the last known change, we don't collapse audits that are after that version.

**I'm open to other ideas. The two goals I'm after:**

1. Cut down audit noise to the user.
2. Cut down how much we're persisting to Author Bus for what is effectively the exact same data.