[Improvement] Handle Route No Match

[ruichen199801]

We can redirect the user to landing page (/) if they go to a route that doesn't exist, and send them an error message.

For better user experience, we can create a 404 not found page when the route doesn't have any matches, like <Route path="*" element={<PageNotFound />} />.

[ruichen199801]

Now user will be shown an error message and get directed to landing page if:

• Search restaurants failed
• Fetch restaurant id failed
• Fetch reviewer id failed
• Visit saved restaurant page / analytics page when not logged in

User will be directed to 404 page without an error message if:

• User hits any other route not included in the above scenarios, such as /notfound, /user/1

It's not necessary to have an exception page for other http error responses such as 500, in which case we expect the app to direct user to landing page.