Split init'ing the wayland output from init
Summary:
This is a tiny refactor so that DrmOutput can have WaylandOutput
dynamically
deleted and recreated at runtime as we disable outptuts.
Reviewers: Plasma, graesslin
Reviewed By: Plasma, graesslin
Subscribers: plasma-devel, kwin, KWin
Tags: KWin
Differential Revision: https://phabricator.kde.org/D8794