Add X-KDE-DBUS-Restricted-Interfaces to Application desktop entry fields

Summary:
This added field to Application desktop entries allows to declare an access request to a DBUS interface.

Needed for D29407

Reviewers: davidedmundson, zzag, Frameworks, KWin, ngraham

Reviewed By: ngraham

Subscribers: kde-frameworks-devel

Tags: Frameworks

Differential Revision: https://phabricator.kde.org/D29774