Time zone support

We have added an optional time_zone field (based on the IANA database time zone values) to the Date objects. Developers can now explicitly set the time zones of Date property values using the time_zone field. Once this property is set explicitly, users will be able to see the same time zone in the app. When time zone information is provided in this method, start and end cannot contain UTC offsets. In addition when time zone information is provided in dates, start and end cannot be dates without time information (i.e. "2020-12-08").

The public API will always return the time_zone field as null when rendering dates and time zone will be displayed as a UTC offset in the start and end date fields.