[gnome-control-center] (8 commits) Non-fast-forward update to branch wip/exalm/appearance

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

The branch 'wip/exalm/appearance' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  e6f6f98... ua: Use the new high contrast key
  577cd74... ua: Stop setting high contrast WM theme
  2192642... background: Redo the layout to match the new mockups
  cfd212c... background: Add a light/dark style switcher
  62d8aca... background: Rename to Appearance
  5697968... background: Clean up the slideshow icon
  ac4bb65... background: Polish wallpaper thumbnails

Commits added to the branch:

  4a5c41b... Update Ukrainian translation (*)
  c1f8e93... ua: Use the new high contrast key
  f89976f... ua: Stop setting high contrast WM theme
  0aaa6f2... background: Redo the layout to match the new mockups
  ecd6124... background: Add a light/dark style switcher
  3fea98b... background: Rename to Appearance
  8887995... background: Clean up the slideshow icon
  5c903af... background: Polish wallpaper thumbnails

(*) This commit already existed in another branch; no separate mail sent