1.add CODE_OF_CONDUCT.md to vLLM Kunlun

2.add MAINTAINERS.md to vLLM Kunlun
3.add MAINTAINERS.md to vLLM Kunlun
4.add contributing guide to vLLM Kunlun

Signed-off-by: tanjunchen <tanjunchen20@gmail.com>

CODE_OF_CONDUCT.md

@@ -0,0 +1,24 @@
+<!--
+#
+# Copyright (c) 2025 Baidu, Inc. All Rights Reserved.
+# 
+# This file is a part of the vllm-kunlun project.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+-->
+
+# Code of Conduct
+
+We follow the vLLM community’s code of conduct: [vLLM - CODE OF CONDUCT](https://github.com/vllm-project/vllm/blob/main/CODE_OF_CONDUCT.md). 
+
+For more information, please refer to the [principles](https://vllm-kunlun.readthedocs.io/en/latest/community/governance.html#principles).