[ADD] Dunst mostly-default configuration file

Dunst is great minimalistic notification daemon. The default config
looks pretty great so I see no need to modify it.

i3/.config/i3/config

@@ -219,6 +219,8 @@ exec --no-startup-id blueman-applet
 exec --no-startup-id nm-applet
 exec --no-startup-id /usr/lib/geoclue-2.0/demos/agent
 exec --no-startup-id redshift-gtk
+# Start dunst notification daemon
+exec --no-startup-id dunst
 # Notify when battery is at 15% and 5% percent
 exec --no-startup-id i3-battery-popup -n -L 15 -l 5