Add menu of librewolf instances

dotfiles/config/bmo/menu.ini

     generator = gowork -f
     consumer = cat
 
+[menu.def.librewolves]
+    mode = items
+    item = librewolf-main
+    item = librewolf-music
+    item = librewolf-learning
+    item = librewolf-gaming
+    item = librewolf-video
+    consumer = sed 's/$/ \&/' | sh -
+
 [menu.def.time_t]
     generator = df -h
     selector = shuf | head -1