FEATURE: Add groupby fields to Dashboards relating to sankey diagrams

[dougburks]

As a defender, I may view a sankey diagram and want to filter or examine certain values from that diagram. We can achieve this by ensuring that there is a separate groupby table for each of the fields in the sankey diagram. To be consistent across all dashboards, we can standardize on a pattern like this:

groupby field1 | groupby -sankey field1 field2 | groupby field2

This displays a sankey diagram showing the relationship between the values in field1 and field2 and also creates separate groupby tables for field1 and field2 so that their values can be examined, filtered, or used in other queries.

[dougburks]

Tested and verified: