gnu: Replace all uses of atk by at-spi2-core.

* gnu/packages/animation.scm (gnash)
* gnu/packages/chromium.scm (ungoogled-chromium)
* gnu/packages/crates-gtk.scm (rust-atk-sys-0.14,
rust-atk-sys-0.10, rust-atk-0.14, rust-gtk-0.14)
* gnu/packages/gimp.scm (gimp)
* gnu/packages/gnome.scm (evince, glade3, clutter, totem, rhythmbox, mutter, ghex):
* gnu/packages/graphviz.scm (xdot)
* gnu/packages/gtk.scm (gtk+-2, gtk+, guile-gnome, atkmm)
* gnu/packages/mate.scm (mate-applets, atril, mate-control-center, mate-calc,
mate-utils, eom, pluma)
* gnu/packages/messaging.scm (dino)
* gnu/packages/qt.scm (qtwebengine-5)
* gnu/packages/rust-apps.scm (alfis)
* gnu/packages/vim.scm (vim-full)
* gnu/packages/vnc.scm (remmina)
* gnu/packages/web.scm (castor): Replace atk by at-spi2-core.

Signed-off-by: Guillaume Le Vaillant <glv@posteo.net>

gnu/packages/chromium.scm

@@ -898,7 +898,6 @@
            wayland))
     (inputs
      (list alsa-lib
-           atk
            at-spi2-core
            cups
            curl