MQTT: remove standalone MQTT clien generator code.
Code was inherited from OPC-UA extension, but not properly maintained.
<?xml version='1.0' encoding='utf-8'?>
<BeremizRoot xmlns:xsd="http://www.w3.org/2001/XMLSchema" URI_location="PYRO://localhost:61131" Disable_Extensions="false">
<TargetType/>
<Libraries Enable_Python_Library="false"/>
</BeremizRoot>