Support DateTime(TimeZone) for Annotations query

[Slach]

current standart expected query is

SELECT 
       toUInt64(event_time) * 1000 AS time,
       (toUInt64(event_time) + (rand() % 600)) * 1000 AS time_end,
       if(rand() % 2 = 1, '[alert] title', '[annotation] title') AS title,
       if(rand() % 2 = 1, '[alert] description', '[annotation] description') AS text,
       arrayStringConcat(['test1', 'test2', service_name],',') AS tags
FROM default.test_grafana
WHERE
  rand() % 100 IN (1,50) AND
  toUInt64(event_time) >= $from AND toUInt64(event_time) < $to

Would be great to use event_time (which have DateTime('timezone')) as is without transformation to UInt64