Support Lateral join and procedure pushdown

Lateral joins of the form:

select ... from x inner join lateral (... x.col ...) as y on ...

Have been supported for some time, but not the ability to push them to source.

A highly related scenario is to be able to push procedures used directly or in lateral joins with the rest of their plan:

select ... from x inner join lateral (call proc(.. x.col ...)) as y on ...