Add a CLI for operating the screen and LEDs w/o running the software

[mbtown01]

Use case here is for setup where the main software isn't running, but we'd like to alert the user to what's going on. With the CLI, we can issue images to the display and operate the lights. Ideas were:

• During setup, show progress and what the current step is
• Clear all status at boot time

It may make sense to create a daemon service that owns both the LED ring and the epaper display (or maybe two daemons). With a simple API bound only to the local host, this daemon could run independently of the main logic and start early. This lets us do things like....

• Simplify what's actually happening in the more critical thermostat logic
• Separate python interpreter so that screen updates don't eat up event time