systemd: add & enable xsettingsd service

Update `dpi` script to interact with systemd units

scripts/dpi

@@ -21,11 +21,9 @@ mkdir -p "$CONF_DIR"
     echo Gdk/UnscaledDPI $(( $dpi*1024/($dpi/96) ))
 } > $CONF_DIR/xsettingsd.local
 
-pid=$(xprop -name xsettingsd _NET_WM_PID 2> /dev/null | awk '{print $NF}')
-if [ -z "$pid" ]; then
-    xsettingsd -c $CONF_DIR/xsettingsd.local &
-else
-    kill -HUP $pid
-fi
-
 echo Xft.dpi: $dpi | xrdb -merge
+xrandr --dpi $dpi
+
+systemctl --user reload-or-restart xsettingsd
+systemctl --user --no-block reload i3
+systemctl --user --no-block restart polybar@i3bar dunst