[FEATURE] Emonio connector

Summary

Emonio meters provide a REST API and an MQTT Client, which allows us to connect to the meters using a custom Connector.

Explain your context

We have defined API connectors in the past. But MQTT has not been used.

What is the expected correct behavior? What was your goal?

Since the meters always measure the same data points, it should be possible to create a meter and its connection/nodes in a standardized way.