added client management panel

- added classes for displaying the client management panel
- added class for displaying the client info
- added page to display a list of clients
- added page to display OpenVpn client information
- added diagram with OpenVpn certificate revocation process

client/ui/pages_logic/ClientManagementLogic.h

@@ -0,0 +1,28 @@
+#ifndef CLIENTMANAGMENTLOGIC_H
+#define CLIENTMANAGMENTLOGIC_H
+
+#include "PageLogicBase.h"
+
+#include "protocols/protocols_defs.h"
+
+class UiLogic;
+
+class ClientManagementLogic : public PageLogicBase
+{
+    Q_OBJECT
+
+    AUTO_PROPERTY(QString, labelCurrentVpnProtocolText)
+
+public:
+    ClientManagementLogic(UiLogic *uiLogic, QObject *parent = nullptr);
+    ~ClientManagementLogic() = default;
+
+public slots:
+    void onUpdatePage() override;
+    void onClientItemClicked(int index);
+
+private:
+    amnezia::Proto m_currentMainProtocol;
+};
+
+#endif // CLIENTMANAGMENTLOGIC_H