Move libmanette to the GNOME group
libmanette is a gamepad access library used by Games, Quadrapassel and soon WebKitGTK (see https://lists.webkit.org/pipermail/webkit-gtk/2020-October/003641.html).
Given it is used by two projects in the GNOME group and given WebKitGTK is an important project, it would be convenient if anybody could handle it to reduce its bus factor by moving it to the GNOME group.
Edited by Adrien Plazas