Allow buying of costumes from past events
Description
Let us buy costumes that were introduced in past events (and are not a part of repeated events).
Rationale
There are some costumes that were only available from certain events like Wanderer's Sakkat which I was told was available from Ninja/Gunslinger introduction event or Spare Card. Assuming they will never be reintroduced, it would be cool if we could simply buy them after the event. This would further promote costumes as money sink and is the easiest way of reintroducing them after the event (some servers add them through custom quests which is obviously a no go here).