Formally deploy mqtt to Birmingham and expose a link to Cardiff

[SamStudio8]

Currently the mosquitto mqtt server is running ad-hoc in Birmingham, as it's being used more we'll need to formalise the deployment to make it safer and robust:

• mosquitto should not run as me
• Implement a mosquitto auth plugin that hooks to Majora (or a script to pull auth keys from Majora)
• Expose a route to Cardiff to allow messages to be exchanged across the two halves of CLIMB-COVID
• Use clean_client to allow clients to pick up missed messages
• Set up an echo service that echoes messages to subscribers only if they meet a template
• Set up an audit client to record all messages

[SamStudio8]

Added to backlog #62

[SamStudio8]

Read up briefly on how this would work. mqtt brokers on different networks can be joined with bridges that just broadcast and subscribe all topics to the other side. I additionally tried to Apache Kafka and kafka-python which is like mqtt on steroids. I think Kafka is overkill for the current phase but looks cool for some stuff I have in mind later.