Data pipeline: add clustered analysis diagram and description (#501)

Author: jonathan-fulton

docs/data-management/data-pipeline.md

@@ -86,3 +86,9 @@ As we’ve detailed, Eppo doesn’t export individual data from your warehouse.
 * **Caching results**: We copy and cache overall results (latest incremental totals, metric patterns) to make our interface snappy. This is any total that you can see on our service: total number of assignments, total number of conversions, total amounts. For ratios, we store the numerator and denominator (for incrementality).
 
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+
+## Clustered Analysis Pipeline
+
+Clustered analysis experiments have a few more steps in the data pipeline to aggregate from the subentity level to the cluster level.  See diagram below with additional steps highlighted.
+
+![Clustered analysis pipeline diagram](/img/experiments/data-pipeline/data_pipeline_clustered_highlighted_v3.png)