Home Assistant MQTT support with Eclipse Paho client

[jmcewen58]

This change has the following:

• Create a new MQTT Producer client using the Eclipse Paho client which can communicate with HomeAssistant.
• Create a wrapper producer client that examines the port supplied in the location, and if > 20,000 uses the original Apache Artemis client, and otherwise uses the Paho client.
• Update the producer server to supply only the wrapper.
• Update bms-to-inverter main fixing bug where external client variable was not used when sending.
• Supply sample yaml config for HomeAssistant, and sample json provided in the MQTT message.

[ai-republic]

@jmcewen58 thanks for your contribution Jeff. I've merged your PR into the main branch 😄
I also added a TODO to add the option to the Configurator to choose the MQTT client/producer implementation. Then it can be split up into separeate modules and can be added via the service loader to keep the footprint small