AttributeUi: add a values list derivation for MAP types

[rpbouman]

We already have a keyset derivation (make an array of the MAP keys), the values list derivation would be its complement (make an array of the MAP values).

It's significance would be to allow filtering.

Example: DuckDB sees the blueworks dataset as an array of records, where each element of records is a MAP(VARCHAR, VARCHAR).

We can currently turn this in to a tabular view by

• putting the element indices of records on the row axis (unnesting the records array)
• putting the key of the entries of the records elements on the columns axis
• putting the max of the value of the entries of the records elements on the cells axis

But, if we now want to see only the objects of a particular type, or of a particular user, we cannot do it.
That is, we can add a filter on the value, but that would result in removal of all fields that happen not to have the values we selected.

If we would have a values list derivation, then we could use an array filter method (has any) to keep only those entries that have the selected filter value.