🪲 DATE functions should accept intervals

[joocer]

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("SELECT DATE_ADD('2022-01-01', INTERVAL 1 DAY)", 1, 1, None),
("SELECT DATE_SUB('2022-01-01', INTERVAL 1 DAY)", 1, 1, None),
("SELECT DATE_DIFF('2022-01-01', '2021-12-31', DAY)", 1, 1, None),