Refactor player managers

src/main/java/emu/grasscutter/game/player/BasePlayerDataManager.java

@@ -0,0 +1,23 @@
+package emu.grasscutter.game.player;
+
+import lombok.NonNull;
+
+public abstract class BasePlayerDataManager {
+    protected transient Player player;
+    
+    public BasePlayerDataManager() {}
+    
+    public BasePlayerDataManager(@NonNull Player player) {
+        this.player = player;
+    }
+    
+    public Player getPlayer() {
+        return this.player;
+    }
+    
+    public void setPlayer(Player player) {
+        if (this.player == null) {
+            this.player = player;
+        }
+    }
+}