Added changes for converting legacy WallpaperInfo classes to the new
model classes

This CL aims at adding convertor utility classes that convert the legacy
wallpaper info classes to the new model classes.

Bug: b/290840060
Test: Tested by building and installing wallpaper picker on local
Change-Id: Id780f855ad2da5dbb3bd4aeed35eccbf51a38433
18 files changed