feat: refactor the settings page architecture

app/src/pages/mod.rs

@@ -0,0 +1,16 @@
+// Copyright 2023 System76 <info@system76.com>
+// SPDX-License-Identifier: GPL-3.0-only
+
+pub mod desktop;
+pub mod networking;
+pub mod sound;
+pub mod system;
+pub mod time;
+
+#[derive(Clone, Debug)]
+pub enum Message {
+    About(system::about::Message),
+    DateAndTime(time::date::Message),
+    Desktop(desktop::Message),
+    External { id: String, message: Vec<u8> },
+}