mqtt message persistence

We want to make sure that workers that subscribe to topic data_parsed are receiving every message, even if they are temporarily disconnected from the broker (updates, bugs, network issues, ...).

• dispatcher services need to subscribe with qos>0 and need to have a unique client_id for this to work.
• extractor/scheduler needs to send the message to topic data_parsed with qos>0

As all other MQTT Settings are passed as ENVVARs, MQTT_QOS will also be passed as ENVVAR from orchestration