[api] Add chunithm profile export and import

[general] Rename some method name and add more docs

src/main/java/icu/samnyan/aqua/sega/general/model/Card.java

@@ -34,6 +34,7 @@ public class Card implements Serializable {
 
     @Column(name = "register_time")
     private LocalDateTime registerTime;
+
     @Column(name = "access_time")
     private LocalDateTime accessTime;