Drop obsolete Shutter screenshot app

Sadly the project died and I haven't found any replacement.

Thanks for all the pixels!

dotfiles/config/i3/config

 ## Less smart apps                                                      ##
 #------------------------------------------------------------------------#
 
-for_window [class="Shutter"]    floating enable
 for_window [class="Orage"]      floating enable
 
 
 exec "urxvt -e weechat"
 exec "nm-applet"
 exec "blueman-applet"
-exec "shutter --min_at_startup"