Allow defining and selecting from set-returning functions

[dullbananas]

https://www.postgresql.org/docs/16/functions-srf.html

For example, this could return [1, 4, 9, 16]

generate_series(1, 4, 1).select(i * i)

[weiznich]

For Feature Request proposals we expect quite a lot more details than: "I want to have this or that".

I would expect at least the following information:

• How does the exact proposed API look like
• What invariants need to be uphold
• What database systems support this syntax
• How would this be implemented (You don't need to provide a complete implementation, but you should at least cover some sketch how something can be represented in the type system)