xwayland: Run scripts from /etc/xdg/Xwayland-session.d
Some hooks need to run on X11 startup. On X11 this is handled by the login manager, for XWayland this is the responsibility of the desktop.
Long term, we want Plasma to make XWayland actually on demand and therefore we should use the initfd for these startup scripts before the application connects.
(cherry picked from commit ce8927c9)
Co-authored-by: David Edmundson kde@davidedmundson.co.uk