Add the create api

1. Created an end point in ApplicationHandler.java
2. Modified JsonPrcHandler.java to add description as return value in
Json object
3. Using rpc to fetch metadata for new creating app in
ApplicationServiceDb.java
Add Create api

Use native jquery in ApplicationServiceDb.java ( in comment is the code
using jpa)
An example to use create api is:
osapi.apps.createApp({appUrl:
"http://widgets.onlinesjtu.com/gadgets/passwortktivitt3.xml"}).execute(function(app){})