chore: add cosmic app list and cosmic panel buttons

applets/cosmic-app-list/src/apps_window/imp.rs

@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: MPL-2.0-only
+
+use crate::apps_container::AppsContainer;
+use gtk4::{glib, subclass::prelude::*};
+use once_cell::sync::OnceCell;
+// Object holding the state
+#[derive(Default)]
+
+pub struct CosmicAppListWindow {
+    pub(super) inner: OnceCell<AppsContainer>,
+}
+
+// The central trait for subclassing a GObject
+#[glib::object_subclass]
+impl ObjectSubclass for CosmicAppListWindow {
+    // `NAME` needs to match `class` attribute of template
+    const NAME: &'static str = "CosmicAppListWindow";
+    type Type = super::CosmicAppListWindow;
+    type ParentType = gtk4::ApplicationWindow;
+}
+
+// Trait shared by all GObjects
+impl ObjectImpl for CosmicAppListWindow {}
+
+// Trait shared by all widgets
+impl WidgetImpl for CosmicAppListWindow {}
+
+// Trait shared by all windows
+impl WindowImpl for CosmicAppListWindow {}
+
+// Trait shared by all application
+impl ApplicationWindowImpl for CosmicAppListWindow {}