chore: refactored lib.rs to move commands into separate folder

src-tauri/src/commands/app.rs

@@ -0,0 +1,14 @@
+use crate::get_app_handle;
+
+#[tauri::command]
+pub fn quit_app() -> Result<(), String> {
+    let app_handle = get_app_handle();
+    app_handle.exit(0);
+    Ok(())
+}
+
+#[tauri::command]
+pub fn restart_app() {
+    let app_handle = get_app_handle();
+    app_handle.restart();
+}