MQTT: remove standalone MQTT clien generator code.
Code was inherited from OPC-UA extension, but not properly maintained.
input,smta,1,DINT,0
input,smtb,1,DINT,1
input,smtc,1,DINT,2
input,smtd,1,DINT,3
input,smte,1,DINT,4
output,smtf,1,False,DINT,0
output,smtg,1,False,DINT,1
output,smth,1,False,DINT,2
output,smti,1,False,DINT,3
output,smtj,1,False,DINT,4