SVGHMI: Makes error when HMI tree is not well formed. Prevents multiple and non-first HMI_NODE, and ensure that all paths in HMI tree are unique.
<?xml version='1.0' encoding='utf-8'?>
<BACnetServerNode xmlns:xsd="http://www.w3.org/2001/XMLSchema" UDP_Port_Number="47808" BACnet_Device_ID="3" BACnet_Communication_Control_Password=" " BACnet_Device_Location="Beremiz lab" Network_Interface="virbr0"/>