MQTT: remove standalone MQTT clien generator code.
Code was inherited from OPC-UA extension, but not properly maintained.
*.pyc
**/__pycache__
.vscode
**/build/**
*.class
**/.svghmithumbs/**
**/my_*.der
**/my_*.pem
tests/tools/Docker/requirements.txt
**/management.json
**/.secret
doc/_build/**
doc/locale/**
C_runtime/**/*.d
C_runtime/**/*.o
beremiz_runtime
**/tmp/**