In a single page application, the url sometimes does not correspond to
the actual resources on the server. Thus, it might cause 404 when users
refresh the page. By redirecting this kind of url back to the homepage,
the proper page can be rendered. If the url does not exist, the front
end will redirect to a Not Found page.
Test: mannual tested.
Change-Id: I36beff436a450ae7fcabe9172df9c7cc217d7305
30f991bf6e