Add property to Windows date picker that allows the user to control what type of calendar they want to display.  #165

Some countries use multiple calendar types, eg. Japan (standard/imperial) or Israel.
Add support for the CalendarIdentifier property exposed by the underlying Xaml control on Windows.

Implementation will follow the same patterns as the existing date format-related props for Windows.

Ref: https://docs.microsoft.com/en-us/uwp/api/windows.ui.xaml.controls.calendardatepicker?view=winrt-18362#globalization