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/qml/Pages/ClientInfo/PageClientInfoBase.qml

@@ -0,0 +1,15 @@
+import QtQuick
+import QtQuick.Controls
+import QtQuick.Layouts
+import PageEnum 1.0
+import ProtocolEnum 1.0
+import "../"
+import "../../Controls"
+import "../../Config"
+
+PageBase {
+    id: root
+    property var protocol: ProtocolEnum.Any
+    page: PageEnum.ClientInfo
+    logic: ClientInfoLogic
+}