Improve DevicesPage and DevicesModel

- Split the list into sections for "this devices", "verified devices", "unverified devices", and "devices without encryption support"
- Sort the lists by last activity

src/models/devicesproxymodel.h

@@ -0,0 +1,25 @@
+// SPDX-FileCopyrightText: 2023 Tobias Fella <tobias.fella@kde.org>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <QSortFilterProxyModel>
+
+class DevicesProxyModel : public QSortFilterProxyModel
+{
+    Q_OBJECT
+    Q_PROPERTY(int type READ type WRITE setType NOTIFY typeChanged);
+
+public:
+    DevicesProxyModel(QObject *parent = nullptr);
+    [[nodiscard]] bool filterAcceptsRow(int source_row, const QModelIndex &source_parent) const override;
+
+    void setType(int type);
+    [[nodiscard]] int type() const;
+
+Q_SIGNALS:
+    void typeChanged();
+
+private:
+    int m_type;
+};