1. Seperate two packages for contrail-webui to contrail-web-core and
contrail-web-controller.
2. contrail-web-core is the base package, when this pkg is installed then only
login page comes if trying to login, then "Install feature package" message gets
displayed.
3. contrail-web-controller is the feature package for contrail-webui.
4. So at run time new web feature package can be installed and uninstalled.
5. All the new package path needs to be added in core config file.
6. At init time, based on the package available, the static file directory
registration, app to URL, job listeners etc. gets registered.