Environment Variable to ensure unique MQTT Client ID

[WillNilges]

Ata found a cool bug where if you're running a client and server instance at the same time, you might have collisions with your MQTT ID.

Should add another environment variable that adds a unique string or something to the MQTT ID so that can't happen between instances.

[WillNilges]

This is also good for development so you don't set off the production devices