added license files for better visiblity

Original commit: elastic/kibana-plugin-helpers@a3297e2728

packages/kbn-plugin-helpers/LICENSE

@@ -0,0 +1,13 @@
+Copyright 2016 Elasticsearch BV
+
+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.

packages/kbn-plugin-helpers/README.md

@@ -26,3 +26,7 @@ $ plugin-helpers help
     -V, --version  output the version number
 
 ```
+
+# License
+
+Apache-2.0