wayland: Add automatic dimming and suspend

Added automatic:

a) screen locking after 5 minutes
b) screen dimming after 10 minutes
c) suspending after 20 minutes

to riverwm. Makes use of swayidle to detect idle times and wlopm to
detect and toggle displays.

wayland/.config/river/init

@@ -3,6 +3,9 @@
 mod="Mod4"
 modemod="Mod1"
 term=${TERMINAL:-foot}
+time_to_lockscreen=300
+time_to_screendim=600
+time_to_suspend=1200
 
 ## OPTIONS
 riverctl spawn "dbus-update-activation-environment SEATD_SOCK DISPLAY WAYLAND_DISPLAY XDG_CURRENT_DESKTOP=river"
@@ -241,8 +244,19 @@ killall waybar
 exec waybar &
 
 # start dynamic display configuration
+killall kanshi
 exec kanshi &
 
+# start screen idle locking/dimming/sleep tool
+killall swayidle
+exec swayidle -w \
+    timeout "${time_to_lockscreen}" 'lockscreen' \
+    timeout "${time_to_screendim}" 'wlopm --off "*"' \
+    timeout "${time_to_suspend}" 'systemctl suspend-then-hibernate' \
+	resume 'wlopm --on "*"' \
+	after-resume 'wlopm --on "*"' \
+    before-sleep 'lockscreen' &
+
 killall clipman
 exec wl-paste -t text --watch clipman store &
 # bash ~/.config/bin/gtktheme # setting our gtk variables