table functions as scalar structs.

[universalmind303]

Description

i'd like to be able to use table functions as scalars for simple select functions.

currently i have to do something like

select first_name from read_parquet('userdata1.parquet')

when I would prefer to just do

select read_parquet('userdata1.parquet').first_name

Internally, we can pretty easily wrap the outputs of the table function as scalar structs instead of recordbatches.