fix(parser)!: CTEs instead of subqueries for pipe syntax

[geooo109]

This PR refactors the whole implementation of the pipe syntax and substitutes the subquery logic to CTEs.
This makes the generated SQL more readable and also solves issues with the scoping of the query columns.

A problem with the previous implementation can be spotted in the following example:

Input:
FROM c.x |> SELECT x.col1, x.col2

Output:
SELECT x.col1, x.col2 FROM (SELECT * FROM c.x)

The subquery "shadows" the scope.

[geooo109]

For the unique name generation of CTEs should we have a state ?

[georgesittas]

LGTM, just a few suggestions.