stream function/type to process array elements one by one

[jinyangli34]

Description

Proposing a new syntax to aggregate array elements in a stream way.
Currently, the array is processed as one value unless using CROSS JOIN UNNEST to process array elements individually.

Additional context and related issues

Usage could be

sum(stream(arr))
max(stream(arr))
approx_distinct(stream(arr))
or nested array: max(stream(stream(arr2)))

#22445

Release notes

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## Section
* Fix some things. ({issue}`22445`)