added PageSetupWizardViewConfig

- added a popup with a question when deleting containers/servers
- added import from code and import error handling

client/core/errorstrings.cpp

@@ -57,6 +57,8 @@ QString errorString(ErrorCode code){
     case (OpenVpnTapAdapterError): return QObject::tr("Can't setup OpenVPN TAP network adapter");
     case (AddressPoolError): return QObject::tr("VPN pool error: no available addresses");
 
+    case (ImportInvalidConfigError): return QObject::tr("The config does not contain any containers and credentiaks for connecting to the server");
+
     case(InternalError):
     default:
         return QObject::tr("Internal error");