This commit moves out non-core wl_surface related code into separate
code units, while renaming types to fit a common scheme. The changes
done are:
* ClutterActor based surface roles built upon
MetaWalyandSurfaceRoleActorSurface. This object has been renamed to
MetaWaylandActorSurface and related functionality has moved into
meta-wayland-actor-surface.c.
* The code related to roles backed by a MetaWindow (i.e. built upon
MetaWaylandShellSurface) was moved into meta-wayland-shell-surface.c
* The majority of subsurface related code was moved into into
meta-wayland-subsurface.c and the object was renamed
MetaWaylandSubsurface.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/5https://bugzilla.gnome.org/show_bug.cgi?id=791938
