WinRT: Locale handling support

Provides locale-related codepaths for WinRT where existing Win32 API is
unsupported.

Change-Id: I35b83d6b208165b7660cac3c9b383cb6ba7e5cf9
Done-with: Maurice Kalinowski
Reviewed-by: Andrew Knight <andrew.knight@digia.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>