bug#58374: GVFS depends on WebKitGTK via gnome-online-accounts

[kiasoc5--- via Bug reports for GNU Guix]

For inspiration, here is Arch Linux's pkgbuild for libgoa, which is 
split from gnome-online-accounts:

https://gitlab.archlinux.org/archlinux/packaging/packages/gnome-online-accounts/-/blob/main/PKGBUILD