Add display timestamp on 'Boards in Archive'

client/components/boards/boardArchive.jade

@@ -14,6 +14,7 @@ template(name="archivedBoards")
             i.fa.fa-undo
             | {{_ 'restore-board'}}
           = title
+        span {{ moment archivedAt 'LLL' }}
     else
       li.no-items-message {{_ 'no-archived-boards'}}