cli: Add timezone to os_date api response

Fixes #558

Add timezone info to the Date/Hour API and CLI response

Reviewed-by: Nadav Har'El <nyh@cloudius-systems.com>
Signed-off-by: Nehal J Wani <nehaljw.kkd1@gmail.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>