update pom license, scm, maillists, issuemanagement, add DISCLAIMER (apache#1491)

Author: jerrick-zhu

DISCLAIMER

@@ -0,0 +1 @@
+Apache Dubbo is an effort undergoing incubation at The Apache Software Foundation (ASF), sponsored by the Incubator. Incubation is required of all newly accepted projects until a further review indicates that the infrastructure, communications, and decision making process have stabilized in a manner consistent with other successful ASF projects. While incubation status is not necessarily a reflection of the completeness or stability of the code, it does indicate that the project has yet to be fully endorsed by the ASF.

dubbo-admin/pom.xml

@@ -1,19 +1,19 @@
 <!--
- - 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.
--->
+  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.
+  -->
 <project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0"
          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
     <modelVersion>4.0.0</modelVersion>