Add 2FA support (#112)

GPClient/challengedialog.h

@@ -0,0 +1,28 @@
+#ifndef CHALLENGEDIALOG_H
+#define CHALLENGEDIALOG_H
+
+#include <QDialog>
+
+namespace Ui {
+class ChallengeDialog;
+}
+
+class ChallengeDialog : public QDialog
+{
+    Q_OBJECT
+
+public:
+    explicit ChallengeDialog(QWidget *parent = nullptr);
+    ~ChallengeDialog();
+
+    void setMessage(const QString &message);
+    const QString getChallenge();
+
+private slots:
+    void on_challengeInput_textChanged(const QString &arg1);
+
+private:
+    Ui::ChallengeDialog *ui;
+};
+
+#endif // CHALLENGEDIALOG_H