Disable Servers settings item when no server has been set

Fix the logic of *Add Server* to comeback to start page instead of push when no server is set

client/ui/qml/Pages/PageGeneralSettings.qml

@@ -120,6 +120,7 @@ PageBase {
                 Layout.preferredHeight: 30
                 icon.source: "qrc:/images/svg/format_list_bulleted_black_24dp.svg"
                 text: qsTr("Servers")
+                enabled: GeneralSettingsLogic.existsAnyServer
                 onClicked: {
                     UiLogic.goToPage(PageEnum.ServersList)
                 }
@@ -137,7 +138,12 @@ PageBase {
                 icon.source: "qrc:/images/svg/control_point_black_24dp.svg"
                 text: qsTr("Add server")
                 onClicked: {
+                    if(GeneralSettingsLogic.existsAnyServer)
+                        // If there is any server set we will go to Start Page
                         UiLogic.goToPage(PageEnum.Start)
+                    else
+                        // Else just come back to start page
+                        UiLogic.closePage()
                 }
             }