docs(core): this adds a new todo

AkamuCore/Sources/AkamuCore/DataLayer/Repositories/Remote/Avatar/Implementations/ServerAvatarRemoteAPI.swift

@@ -25,6 +25,7 @@ class ServerAvatarRemoteAPI: AvatarRemoteAPI {
     }
 
     func getAvatar(with id: Int) -> Single<Avatar> {
+        // TODO: Single avatar endpoint
         getUnlockedAvatars().map { avatar -> Avatar in
             avatar.first { $0.id == id } ?? Avatar.getDefault()
         }