Removed Gnome from offline repo

contrib/rootfs/offline_repo.json

@@ -31,12 +31,6 @@
             "pkgdescription": "Tool zum visualisieren von Graphen",
             "tagged": true
         },
-        {
-            "pkgname": "gnome",
-            "pkgdescription": "GNOME3 Desktop Umgebung",
-            "tagged": false,
-            "hidden": true
-        },
         {
             "pkgname": "xubuntu-desktop",
             "pkgdescription": "Xubuntu Desktop Umgebung und standard Programme",