Support dynamic output enabling/disabling from KScreen
Summary:
We need to keep the DrmOutput object to still have the
WaylandOutputDevice.
Screens currently start off enabled as before.
In order to keep KWin to have a correct index based list of screens we
need to store a second vector of currently enabled outputs for the
screens interface.
Test Plan:
Had dual screens.
Disabled/Enabled each one through the kscreen KCM
Reviewers: Plasma, graesslin
Reviewed By: Plasma, graesslin
Subscribers: ngraham, luebking, broulik, graesslin, plasma-devel, kwin, KWin
Tags: KWin
Differential Revision: https://phabricator.kde.org/D8796