Add icons for XDG publicshare and templates dirs
In the home folder for new users the directories "Public" and "Templates" stand out, because they do not have a special icon. Icons for them are available in Breeze, but not used as Qt does not implement them as StandardPaths (QTBUG-86106 and QTBUG-78092). The change here adds icons for both folders by looking up the XDG directories and adding them to the map of standard locations.
Edited by Björn Feber