fix session timeout issue

removed tiles
various small cleanups
added session service to aid in debugging session issues

java/org/owasp/webgoat/controller/Start.java

@@ -6,7 +6,6 @@
 package org.owasp.webgoat.controller;
 
 import javax.servlet.http.HttpServletRequest;
-import javax.servlet.http.HttpSession;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestMethod;