Utility function for disabling chronicle

[simonw]

I built this like so for:

• Plugin design datasette/datasette-chronicle#1

    def disable(conn):
        conn.execute('DROP TABLE "{}"'.format(chronicle_table))
        # And remove the triggers
        for trigger in (
            "_chronicle_{}_ai".format(table),
            "_chronicle_{}_ad".format(table),
            "_chronicle_{}_au".format(table),
        ):
            conn.execute('DROP TRIGGER "{}"'.format(trigger))

    await db.execute_write_fn(disable)

A sqlite_chronicle.disable_chronicle(conn, table) utility function would be neater.