Add supportedSchemes feature
Summary:
This addds a whitelist of supported URL schemes to the KFileWidget
to be used by KDEPlatformFileDialog. The whitelist is used by the
KFilePlacesModel and KDirOperator to filter the displayed contents.
Reviewers: Plasma, dfaure
Subscribers: plasma-devel, Frameworks
Tags: Plasma, Frameworks
Differential Revision: https://phabricator.kde.org/D10024