Using a single dd command fails sometimes.

The image needs to be available to the guest with a partition table and
a partition with a label named "nixos" so the stage1 can mount it. By
enabling the virtualisation.diskImage option we now have a persistent
root filesystem, including /home.

Flake lock file updates:

• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/c3e128f3c0ecc1fb04aef9f72b3dcc2f6cecf370' (2024-01-15)
  → 'github:rodarima/nixpkgs/57e7c8fa4fdc414a936ce83afd0c70fb0a3a31d5' (2024-01-24)

There is a problem in the way pkgsStatic is constructed, causing our
-march argument to be missed, leading to binaries that fail to run. This
affects only security wrappers so far (mount, sudo, ...) but it will
likely affect any pkgsStatic binary.

The march and mtune flags are passed by the crossSystem gcc attributes,
which are placed *before* the flags to gcc. This may end up causing some
packages to break, but it is working fine so far.