Add missing rules for LISTAGG & UNNEST

[jogrogan]

SQL functions were still not fully working with #112. The tests were only testing views, creation of materialized views, when walking the implementor path, uncovered a few issues.

• Added LogicAggregate rule to support LISTAGG
• Added Uncollect rule to support UNNEST

There are still feature gaps present

create or replace view ADS."unnested" AS SELECT * FROM UNNEST(ARRAY(SELECT "FIRST_NAME" FROM profile.members)) AS name;

This still fails expected rules for Collect and LogicalValues. Hit a roadblock with Collect which is missing RelToSqlConverter conversion so gave up on that for now.

[ryannedolan]

Nice work!