Migrate away from vmdebootstrap (and possibly from Vagrant)
We use vmdebootstrap to build the VM image used for building Tails ISO images with Vagrant (vagrant/definitions/tails-builder/generate-tails-builder-box.sh)..) vmdebootstrap barely made it in Buster and might not be in Bullseye.
Sources of inspiration:
And wrt. replacing Vagrant altogether, see:
- vagrant-libvirt has no maintainer as of 2020-02-14
- #7580 (closed) and https://tails.boum.org/blueprint/replace_vagrant/
- #7530 (closed) and https://tails.boum.org/blueprint/evaluate_Docker/