Named timezone support in Power BI

[jmgore75]

Currently in PowerBI you can only change timezones by way of numeric arithmetic. This greatly complicates the handling of time, especially with respect to daylight savings time. It would be easier if we could handle timezones using standard naming conventions. 

There are three places where named timezone support would be justified, in order of importance:

1. Via functions in Power Query
2. Via functions in DAX, along with DateTimeZone support
3. In Power BI:
   1. Add datetimezone data type support (as in power query)
   2. Ability to specify the timezone for a datetime column, manually or using another field. UTC should be the default presumed timezone, but a report should be able to specify another default timezone
   3. Ability to present a datetimezone or datetime with a configured zone in a different timezone. This could replace the unused for datetime "Data Category" field in the UI.