Update opensuse links to point to latest release and SUSE LLC IP

• We should probably update to Novell to SUSE LLC
• Override openSUES Leap 42.3 (which is displayed as latest) with the latest stable 15.X version

My primary motivation was to get up2date version in the flatpak version which seems to be pulling data from here https://github.com/flathub/org.gnome.Boxes

Current gnome-boxes / recommended downloads display openSUSE Leap 42.3 which is several years old. See attached screenshot