Support nested datatypes like json columns

[aszenz]

Feature Request

Description of Problem:

I have a dataset with a json column custom_fields, I want to extract one of the fields from this column and show it as a sep col so that user can filter/sort and group by it.

Potential Solutions:

Support decoding json in expression language, so we can easily extract out fields from nested data types like json.

Not sure there is an alternative solution here, maybe regex to parse json?