Move remaining code to app module

There's still some stuff that could potentially go elsewhere but I think it's enough for now.

src/app/qml/AvatarTabButton.qml

@@ -0,0 +1,59 @@
+// SPDX-FileCopyrightText: 2021 Devin Lin <espidev@gmail.com>
+// SPDX-FileCopyrightText: 2021 Noah Davis <noahadvs@gmail.com>
+// SPDX-License-Identifier: LGPL-2.0-or-later
+
+import QtQuick
+import QtQuick.Layouts
+import QtQuick.Controls as QQC2
+import QtQuick.Templates as T
+import org.kde.kirigami as Kirigami
+import org.kde.kirigamiaddons.delegates as Delegates
+import org.kde.kirigamiaddons.labs.components as KirigamiComponents
+
+Delegates.RoundedItemDelegate {
+    id: root
+
+    property url source
+
+    property alias notificationCount: avatarNotification.notificationCount
+
+    property alias notificationHighlight: avatarNotification.notificationHighlight
+
+    property alias showNotificationLabel: avatarNotification.showNotificationLabel
+
+    signal contextMenuRequested
+    signal selected
+
+    padding: Kirigami.Units.largeSpacing
+
+    QQC2.ToolTip.visible: hovered
+    QQC2.ToolTip.text: text
+    QQC2.ToolTip.delay: Kirigami.Units.toolTipDelay
+
+    Accessible.onPressAction: selected()
+    Keys.onSpacePressed: selected()
+    Keys.onEnterPressed: selected()
+
+    TapHandler {
+        acceptedDevices: PointerDevice.Mouse | PointerDevice.TouchPad | PointerDevice.Stylus
+        acceptedButtons: Qt.RightButton | Qt.LeftButton
+        onTapped: (eventPoint, button) => {
+            if (button === Qt.RightButton) {
+                root.contextMenuRequested();
+            } else {
+                root.selected();
+            }
+        }
+    }
+
+    TapHandler {
+        acceptedDevices: PointerDevice.TouchScreen
+        onLongPressed: root.contextMenuRequested()
+    }
+
+    contentItem: AvatarNotification {
+        id: avatarNotification
+        source: root.source
+        name: root.text
+    }
+}