[FEA] Support months_between for not UTC time zones

[revans2]

Is your feature request related to a problem? Please describe.
The current implementation of months_between works most of the time for other time zones. But it does not work all of the time. The issue is when calculating the number of seconds into a given day we end up with the wrong answer because there could be a time zone transition between the start date and the timestamp.

Describe the solution you'd like
Some way to calculate the start of a day in a different time zone. I am not 100% sure how to do that. Will need to look into it a little bit more.