Reduce #ifdef PHOC_XWAYLAND
Let's move the XWayland setup in PhocDesktop
into its own file so we can remove the number of PHOC_XWAYLAND
conditionals. Also move some PhocXWaylandSurface related logic out of generic code into the class.
We can do some more here but wlroots 0.19.x renames some _or_
functions to (the nicer) _override_redirect_
so lets do that bit once we've updated to 0.19. Also stuff in Phoc{Output,Render}
can go away when we rework the surface handling.
Marking as draft as this is on 0.18.x. Will rebase once that landed.
Edited by Guido Günther