Enable 791 format roundtrip tests by adding missing Format support

[kyleconroy]

Key changes:

• Add INSERT VALUES parsing and formatting
• Add DETACH/ATTACH statement support
• Add DROP DICTIONARY support
• Add UNION ALL/DISTINCT/EXCEPT/INTERSECT formatting
• Improve format normalization for whitespace, operators, joins, etc.
• Add numeric underscore normalization (100_000 -> 100000)
• Add backtick identifier normalization
• Normalize ENGINE = X to ENGINE X
• Normalize INNER JOIN to JOIN
• Normalize ORDER BY ASC (default)
• Normalize CROSS JOIN to comma
• Normalize INSERT INTO TABLE to INSERT INTO
• Normalize OFFSET ROWS to OFFSET
• Normalize backslash escaping in strings
• Remove space before column list in INSERT