HaikuDepot: Featured Pkgs View

This change will move the display of the featured packages
from a dynamic layout to one that is static. This should
improve layout consistency and ui performance as well as
introduce keyboard navigation in the featured packages
list.

Resolves #11675, #15012
Helps #14675

Change-Id: Iddac7a9562763c7a890ec5dcf633e94f84684f43
Reviewed-on: https://review.haiku-os.org/c/haiku/+/2708
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>