Implement model, controller and UI for killswitch dns exceptions

client/ui/models/allowed_dns_model.h

@@ -0,0 +1,37 @@
+#ifndef ALLOWEDDNSMODEL_H
+#define ALLOWEDDNSMODEL_H
+
+#include <QAbstractListModel>
+#include "settings.h"
+
+class AllowedDnsModel : public QAbstractListModel
+{
+    Q_OBJECT
+
+public:
+    enum Roles {
+        IpRole = Qt::UserRole + 1
+    };
+
+    explicit AllowedDnsModel(std::shared_ptr<Settings> settings, QObject *parent = nullptr);
+
+    int rowCount(const QModelIndex &parent = QModelIndex()) const override;
+    QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
+
+public slots:
+    bool addDns(const QString &ip);
+    void addDnsList(const QStringList &dnsServers, bool replaceExisting);
+    void removeDns(QModelIndex index);
+    QStringList getCurrentDnsServers();
+
+protected:
+    QHash<int, QByteArray> roleNames() const override;
+
+private:
+    void fillDnsServers();
+
+    std::shared_ptr<Settings> m_settings;
+    QStringList m_dnsServers;
+};
+
+#endif // ALLOWEDDNSMODEL_H