Merged PR 4887: Adds audit helper + finishes KPIs Refactor Stage 1

# Description

Adds audit helper.
Removes computation of Total and Retained Revenue from cross models.

I've tested audit helper and the trick with the hashes, as discussed in the demo.

# Checklist

- [X] The edited models and dependants run properly with production data.
- [X] The edited models are sufficiently documented.
- [X] The edited models contain PK tests, and I've ran and passed them. **Except for today's outlier detector!**
- [X] I have checked for DRY opportunities with other models and docs.
- [X] I've picked the right materialization for the affected models.

# Other

- [ ] Check if a full-refresh is required after this PR is merged.

Related work items: #28946

package-lock.yml

@@ -5,6 +5,8 @@ packages:
     version: 0.9.0
   - package: dbt-labs/dbt_utils
     version: 1.2.0
+  - package: dbt-labs/audit_helper
+    version: 0.12.1
   - package: calogica/dbt_date
     version: 0.8.1
-sha1_hash: ceec21d8037429db57330b6f23cfdc761bbb7698
+sha1_hash: ef447e4c6ef3a63e0f8fa3d3ec7db2f888bb0930