Support WITH clause also in subqueries like PostgreSQL

PostgreSQL supports a `with` clause in subqueries, but CockroachDB doesn't. Would be nice to add support for that. Here a sample query:

```sql
select (
with recursive a as (
select 1 v
union all
select r.v + 1
from a r
where r.v < 10
)
select count(*) from a
)
```

This is just a toy example, but the nice thing about this feature, is that we can do "lateral" recursive queries i.e. a recursive query per outer row.

Jira issue: CRDB-42337