Make some chr stats nullable to ease migration to PG

src/main/java/net/server/world/Party.java

@@ -44,7 +44,7 @@ import java.util.concurrent.locks.ReentrantLock;
 
 public class Party {
 
-    private int id;
+    private final int id;
     private Party enemy = null;
     private int leaderId;
     private final List<PartyCharacter> members = new LinkedList<>();
@@ -173,10 +173,6 @@ public class Party {
         return id;
     }
 
-    public void setId(int id) {
-        this.id = id;
-    }
-
     public int getLeaderId() {
         return leaderId;
     }