We need to create a way for completely automatic installation, which will be available out of the box.

We already have some tools available, for example, a custom user-data handler for Cloud-init, which can do this. Now it is time to make this feature a part of the main sources.

We can reuse a lot of tools from https://github.com/vyos/vyos-1x/pull/1768, which should speed up development significantly.

I think, the feature should be implemented as a Cloud-init module, because all the rest parts like system pre-configuration and multiple environments support are already there, and we only need to take care about moving files to the proper places on a disk and installing GRUB.