Add support for Surface enter/leave events
Summary:
This change implements support for the wl_surface events enter and
leave. Those events are emitted whenever a surface becomes visible on
an output by e.g. mapping the surface, moving or resizing it. Similar
the leave is sent whenever the surface is no longer on an output.
The server side is not yet fully complete yet. It also needs to emit
when the client binds the output another time and needs to send a
leave before destroying the output.
Reviewers: Plasma on Wayland
Subscribers: plasma-devel
Tags: Plasma on Wayland
Differential Revision: https://phabricator.kde.org/D2528