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/ConfirmUrlDialog.qml

@@ -0,0 +1,28 @@
+// SPDX-FileCopyrightText: 2024 Tobias Fella <tobias.fella@kde.org>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+import QtQuick
+import QtQuick.Controls as QQC2
+
+import org.kde.kirigami as Kirigami
+
+Kirigami.PromptDialog {
+    id: root
+
+    property url link
+
+    title: i18nc("@title:dialog", "Open URL")
+    subtitle: xi18nc("@info", "Do you want to open <link>%1</link>?", root.link)
+    dialogType: Kirigami.PromptDialog.Warning
+
+    standardButtons: QQC2.DialogButtonBox.Open | QQC2.DialogButtonBox.Cancel
+
+    onAccepted: {
+        Qt.openUrlExternally(root.link);
+        root.close();
+    }
+
+    onRejected: {
+        root.close();
+    }
+}