Create 'KFilePlacesModel::convertedUrl' static function
Summary:
Move convertedUrl from KFilePlacesView to KFilePlacesModel to be reused
by other views that use the same model.
Depends on D8332
Depends on D8434
Depends on D8348
Test Plan: unit test created
Reviewers: dfaure
Reviewed By: dfaure
Subscribers: ngraham, Frameworks
Tags: Frameworks
Differential Revision: https://phabricator.kde.org/D8943