[SavedObjects] Let's try to figure out how to add aggregation/aggs

[XavierM]

Describe the feature:
Solutions in Kibana are using saved-object for their CRUD and it will also need the feature of aggregation for Elastic search back to saved objects.

Describe a specific use case for the feature:
In SIEM solutions, we need it for case management, timeline to bring back some good KPIs to our user and also to find gaps in our signals in Detections

[XavierM]

#64002

[pgayvallet]

This has been implemented, I'll go ahead and close this.