[dashboard] Implement 404 page

Author: jankeromnes

components/dashboard/src/App.tsx

@@ -106,6 +106,12 @@ function App() {
                 <Route path={["/admin"]} exact>
                     <Redirect to="/admin/users"/>
                 </Route>
+                <Route path="*" /* status={404} */>
+                    <div className="mt-48 text-center">
+                        <h1 className="text-gray-500 text-3xl">404</h1>
+                        <p className="mt-4 text-lg">Page not found.</p>
+                    </div>
+                </Route>
             </Switch>
         </div>
     </Route>;