Automatically change Plasma theme between dark and light
- Place timer and service file in the respective user directory $HOME/.config/systemd/user
 - Place the script into a directory and specify the path in the service file.
 - Change time in script if necessary (default is 9:30 p.m. and 6:00 a.m.)
 - Alternatively use the themer-sun.sh script to change themes according to your locations sunrise/sunset
 - Enable and start the timer:
$ systemctl --user enable themer.timer
$ systemctl --user start themer.timer