Improve security of MQTT system through authentication

[Arizbethrojas]

Is your request related to a problem? Please describe.
Currently, connections on the MQTT system are not authenticated, which introduces vulnerabilities as far as who can access the system and what they can do. To avoid this, we should establish authentication and authorization routines.

Describe the solution you'd like

• use TLS with certificate credentials from certificate authority (CA) for all connections.
• Inbound ports on MQTT system should be disabled at the the edge clients
• Only TCP/IP ports (8883, 443) should be open on the MQTT server
• Use username and password for MQTT clients at servers