Remove useless class ClassicLibrary (#2621)

HMCLCore/src/main/java/org/jackhuang/hmcl/game/ClassicLibrary.java

@@ -1,26 +0,0 @@
-/*
- * Hello Minecraft! Launcher
- * Copyright (C) 2020  huangyuhui <huanghongxun2008@126.com> and contributors
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
-package org.jackhuang.hmcl.game;
-
-/**
- *
- * @author huang
- */
-public class ClassicLibrary {
-
-}