do not reload index.jsp after every request to the server

init jquery datatable on browser load (rm of onload attr from body)

use min versions of jquery and jquery plugins

add images dir necesseray for datatable plugin

refactoring of server side classes and return codes and content types

refactoring of client side js

rm of jstl tag library (from pom.xml as well)

Change-Id: I486adb3b4be34e55e4728740c7f44226be8a7a5d