Concatenate in JSON Array Format in Visual Window and Group By Recipies

User Story:

As a data analyst who uses Dataiku Visual Join and Window Recipes, from time to time I'd like to be able to concatenate values as JSON Arrays. (Not simply with a separator based approach.). This would allow for quicker use of Join and Window Recipie. Maybe not requiring a followup prepare recipie

COS:

• Current Default behavior should remain
• Documentation should be complete
• It would be nice if the JSON version knew the datatype and did the correct thing.

Notes:

Many times I will concatenate with the separator "," and then create a seperate recipie to add the [" and "] on the results of a concatenate.