Add Direct Query Function

[theory]

clickhouse_raw_query() currently collects and displays all the results of a query as a single TEXT value. Determine whether it'd be feasible to provide a similar function that takes a native ClickHouse query but maps the return values to Postgres data types and column names and displays them like table, as table-returning functions to. This similar to how JSON_TABLE works; see if we can borrow the code there to dynamically determine column names and types.