D8367: Hidding place groups implementation in KFilePlacesModel

[Nathaniel Graham]

ngraham added a dependent revision: D8450: User can now hide an entire places 
group from KFilePlacesView.

REVISION DETAIL
  https://phabricator.kde.org/D8367

To: mlaurent, renatoo, ngraham, franckarrecot, ervin
Cc: ngraham, mlaurent, #frameworks