D6811: Use std::bind expression for Workspace::slotWindowtoDesktop

[Martin Flöser]

graesslin added a dependency: D6783: Replace Workspace::slotWindowQuickTileFoo 
by a quickTileWindow with argument.

REVISION DETAIL
  https://phabricator.kde.org/D6811

To: graesslin, #kwin, #plasma
Cc: plasma-devel, ZrenBot, progwolff, lesliezhai, ali-mohamed, jensreuterberg, 
abetts, sebas, apol, mart, lukas