sway/config: Launch swayidle and kanshi from systemd

Launch swayidle and kanshi from systemd user session instead of via
sway's config. This way they bind to the sway-session target and s-
tart/stop automatically when sway is started/stopped. As a bonus,
they don't get launched again when you reload sway.

See: https://github.com/swaywm/sway/wiki/Systemd-integration

sway/config

@@ -51,9 +51,6 @@ output * bg /usr/share/backgrounds/sway/Sway_Wallpaper_Blue_1920x1080.png fill
 #
 # You can get the names of your outputs by running: swaymsg -t get_outputs
 
-# Manage outputs with kanshi
-exec_always pkill kanshi; exec kanshi
-
 # Wayland overlay bar for sound and brightness level
 exec mkfifo $SWAYSOCK.wob && tail -f $SWAYSOCK.wob | wob
 
@@ -61,13 +58,10 @@ exec mkfifo $SWAYSOCK.wob && tail -f $SWAYSOCK.wob | wob
 #
 # Example configuration:
 #
-set $lock_bg ~/Downloads/3121px-Jerusalem-2013-Temple_Mount-Dome_of_the_Rock-Detail_01.jpg
-
-exec swayidle \
-    timeout 300 'swaylock -c 000000 -i $lock_bg' \
-    timeout 600 'swaymsg "output * dpms off"' \
-       resume 'swaymsg "output * dpms on"' \
-    before-sleep 'swaylock -c 000000 -i $lock_bg'
+# exec swayidle -w \
+#          timeout 300 'swaylock -f -c 000000' \
+#          timeout 600 'swaymsg "output * dpms off"' resume 'swaymsg "output * dpms on"' \
+#          before-sleep 'swaylock -f -c 000000'
 #
 # This will lock your screen after 300 seconds of inactivity, then turn off
 # your displays after another 300 seconds, and turn your screens back on when
@@ -275,3 +269,6 @@ bar {
 }
 
 include /etc/sway/config.d/*
+
+# Start sway-session.target, to which kanshi.service and swayidle.service bind.
+exec_always "systemctl --user import-environment; systemctl --user start sway-session.target"