D11075: Make Okular show the list of opened windows in the Dock menu

[Sergio Bragin]

sbragin added a dependency: D11074: Fix opening files via a file manager on Mac.

REPOSITORY
  R223 Okular

REVISION DETAIL
  https://phabricator.kde.org/D11075

To: sbragin
Cc: rjvbb, #okular, michaelweghorn, ngraham, aacid