Parse ARRAY_AGG for Bigquery and Snowflake

[SuperBo]

There are subtle differences of ARRAY_AGG in SQL dialects:

1. https://jakewheat.github.io/sql-overview/sql-2016-foundation-grammar.html#array-aggregate-function
2. https://docs.snowflake.com/en/sql-reference/functions/array_agg.html
3. https://cloud.google.com/bigquery/docs/reference/standard-sql/aggregate_functions
4. https://www.postgresqltutorial.com/postgresql-aggregate-functions/postgresql-array_agg/

This the very first attempt to support correct ARRAY_AGG function while parsing BigQuery and snowflake.