Remove obsolete saturnin-iam command

dotfiles/saturnin/dmenu.ini

 [dmenu.item]
     iam:AFK         = saturnin iam afk
     iam:GONE        = saturnin iam gone
-    iam:MOVING      = saturnin iam moving
     iam:BACK        = saturnin iam back
     iam:UNDOCKING   = saturnin iam undocking
     iam:ZLEEPING    = urxvt -title 'iam:ZLEEPING' -e saturnin iam zleeping