Umbrel OS

[lukechilds]

Just a quickly thrown together example of how Umbrel OS builds could be done.

In a mergeable version:

• The local Umbrel installation would be installed in the image, not a hardcoded version pulled down via git.
• Vanilla Debian would be used as a base image so we don't have to clean up all the Pi OS stuff.
• The provision script would be idempotent so we have a single place to keep track of all dependencies and configurations and we re-run the script after each ota update.
• We would add multiple build targets: Raspberry Pi, x86, etc.

This was just quickly thrown together as I needed the resulting image to test some things. I'll be focusing on other higher priority issues and won't be continuing on this. If anyone else wants to take this on, feel free.

@AaronDewes I know you've been playing around with vmdb2. If you think swapping out Packer for vmdb2 can simplify this process even more then even better.