Printers window peristence

implemented using same pattern as Screen preferences
made corrections from review

Fixes #4262

Change-Id: I658baebcdc6ef7809d871b61db75d0b4099937ed
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3870
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>