Recursive planner should pushdown filters into the recursively planned queries

As an example, look at the following query. The filter ` ANY(ARRAY[2, 1, 6])` on the outer query is safe to pushdown to the subquery before it is recursively planned

```SQL
SELECT count(*)
FROM users_table u1
JOIN
(SELECT value_1,
random()
FROM users_table) AS u2 USING (value_1)
WHERE u2.value_1 > ANY(ARRAY[2, 1, 6]);
```

Currently produces the following query:
```SQL
SELECT value_1, random() AS random FROM sc1.users_table_102396 users_table WHERE true
```

However, it should be safe to do
```SQL
SELECT value_1, random() AS random FROM sc1.users_table_102396 users_table WHERE users_table.value_1 > ANY(ARRAY[2, 1, 6]);

```

A basic prototype: https://github.com/citusdata/citus/pull/2504/commits/3ac4c1c3a2d59213133ec0f47b585ad4c6a5bce6 and some tests: https://github.com/citusdata/citus/pull/2504/commits/6b2a412c12d885e01bc5ec4ab0577e5b6a507cbd