[HELIX-198] Unify helix code style, rb=13710, add missing header

Author: zzhang5

helix-style.xml

@@ -1,4 +1,23 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!--
+Licensed to the Apache Software Foundation (ASF) under one
+or more contributor license agreements.  See the NOTICE file
+distributed with this work for additional information
+regarding copyright ownership.  The ASF licenses this file
+to you 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.
+-->
+
 <profiles version="12">
 <profile kind="CodeFormatterProfile" name="Helix" version="12">
 <setting id="org.eclipse.jdt.core.formatter.comment.insert_new_line_before_root_tags" value="do not insert"/>