Copy some files from Grasscutter-Quests

NOT completely finished, nor is it completely done. Protocol issues remain! (including lack of packet IDs)

src/main/java/emu/grasscutter/game/activity/ActivityConfigItem.java

@@ -14,7 +14,19 @@ public class ActivityConfigItem {
     int scheduleId;
     List<Integer> meetCondList;
     Date beginTime;
+    Date openTime;
+    Date closeTime;
     Date endTime;
 
     transient ActivityHandler activityHandler;
+
+    void onLoad() {
+        if (openTime == null) {
+            this.openTime = beginTime;
+        }
+
+        if (closeTime == null) {
+            this.closeTime = endTime;
+        }
+    }
 }