Sqlsmith: Sql feature generation

[kwannoel]

As we add more features, these should be tested via sqlsmith as well.

SQL Features:

• Generate other table functions: generate_series, unnest. See: sqlsmith: Generate table function #4540
• Generate array_agg, jsonb_agg, jsonb_object_agg
• Generate select from System Tables
• Generate NATURAL JOIN
• Generate JOIN with USING
• Generate query w/o GROUP BY
• Randomly toggle session variables
• Generate pow/exp.
• Generate TopN by group: https://www.risingwave.dev/docs/current/sql-pattern-topn/
• Generate jsonb exprs, see: Tracking: jsonb operations #7714
• sqlsmith: Generate struct and list exprs #7132
• Generate order-by-clauses with NULLS { FIRST | LAST } (will be done in 000cbc1)
• Generate max,min,count for timestamptz
• Generate bit_and, bit_or and big_xor in batch queries, and bit_xor in streaming queries.
• Generate array range access.
• sqlsmith: test EOWC #10241
• Generate window functions other than row_number, rank.
• Generate ALTER DDL statements.\
• Support SELECT * EXCEPT in sqlsmith #10516
• Generate temporal filter in sqlsmith