add license to webapp folder which is missed by default setup of gradle license plugin.

mifosng-provider/src/main/webapp/META-INF/context.xml

@@ -1,4 +1,9 @@
 <?xml version="1.0" encoding="UTF-8"?>
+<!--
+    This Source Code Form is subject to the terms of the Mozilla Public
+    License, v. 2.0. If a copy of the MPL was not distributed with this file,
+    You can obtain one at http://mozilla.org/MPL/2.0/.
+-->
 <Context>
   <ResourceLink name="jdbc/mifosplatform-tenants" global="jdbc/mifosplatform-tenants" type="javax.sql.DataSource" />
 </Context>

mifosng-provider/src/main/webapp/WEB-INF/web.xml

@@ -1,4 +1,9 @@
 <?xml version="1.0" encoding="UTF-8"?>
+<!--
+    This Source Code Form is subject to the terms of the Mozilla Public
+    License, v. 2.0. If a copy of the MPL was not distributed with this file,
+    You can obtain one at http://mozilla.org/MPL/2.0/.
+-->
 <web-app 
   xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" 
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"