It is important that we end plasma-core.target plasma-workspace.target
and graphical-session.target when we log out. graphical-session in turn
closes all other apps and daemons and prevents restarts.
Handling it in systemd gives the least racey option.
graphical-session used to be hanlded in the plasma-ksmserver service
file, but this was removed in 5.24 in a refactor where it caused issues
for Xwayland restarting.
This patch reintroduces the sentinel programs to close down our target,
which in turn take down the other targets. It also removes a complicated
use of templates that in hindsight didn't really solve anything.
BUG: 448492
Testing done:
- logout of wayland shows all targets as inactive, logging in
repeatedly works smoothly
- logout of X11 behaves the same.
- calling systemctl --user stop plasma-kwin_wayland.service closes the
session
- killing ksmserver on wayland does not close the session
- killing ksmserver on X does
David Edmundson