Rework user types: create AuthenticatedUser and AnonymousUser class

Both are subclasses of an abstract User class which contains almost everything
interesting.

express/basic/routes.ts

@@ -24,7 +24,14 @@ const routes: Record<string, Route> = {
             const me = request.session.getUser();
 
             const email = me.toString();
-            const c = await render("basic/home", { email });
+            const showLogin = me.isAnonymous();
+            const showLogout = !me.isAnonymous();
+
+            const c = await render("basic/home", {
+                email,
+                showLogin,
+                showLogout,
+            });
 
             return html(c);
         },