UI: list headers: show the card count smaller

The card count was at the same level than the title, which made
reading the list title harder. Use the quiet and small class
to put it in the following line and not make it jump out of the screen

client/components/lists/listHeader.jade

@@ -15,9 +15,8 @@ template(name="listHeader")
          |/#{wipLimit.value})
 
         if showCardsCountForList cards.count
-          = cards.count
-          span
-            |  {{_ 'cards-count'}}
+          | 
+          p.quiet.small {{cards.count}} {{_ 'cards-count'}}
       if isMiniScreen
         if currentList
           if isWatching