support geographical time zone in statistic - Agent

Given I want statistic for a month that include daylight-saving-time change (e.g. November for America/Montreal includes a 25-hour day)
Given I request /queues/statistics with query string from=..-0400&until=..-0500
Then I will receive range of 1 month and 1 hour (31 entries, the last for December 1st)
Expected: I receive range of only one month (30 entries, the last for November 30th)

Currently the API /queues/statistic doesn't know about the geographical time zone and cannot do some logic about time change.
Moreover, if you add day_start_time and day_end_time, only the timezone of the from will be taken into account and your result will be wrong for a part of the month
You can easily port this scenario with a range of year. you will have ~ 6 months with your opened hour wrong

Technically:
Backend need to know the time zone (ex: America/Montreal), not only the offset, to know when the time change as occurs.