Allow to build against Debian Bullseye too

See merge request Librem5/image-builder!164

On PureOS Amber that is less of a concern since it's stable now (and we
could use pinning) and on bullseye we don't care yet

Update ci repo key

See merge request Librem5/image-builder!163

I thought we'd get them but it's stored in the repo. This
will move into a deb package too.

Temporarily drop gnome-dev from x86 images

See merge request Librem5/image-builder!162

It can't install due to

Librem5/librem5-base!136

so let's drop that until the package migrated.

board: Adjust to branch rename

See merge request Librem5/image-builder!161

The linux-next branch lost it's 'linux-' to avoid confusion
with upstream's linux-next tree.

Don't inherit MIRROR from environment

See merge request Librem5/image-builder!158

Increase max size of image

See merge request Librem5/image-builder!160

x86_64 qemu images are failing to build in Jenkins.

https://arm01.puri.sm/job/Images/job/Image%20Build/3568/console

    update-initramfs: Generating /boot/initrd.img-4.19.0-5-amd64
    cp: error writing '/var/tmp/mkinitramfs_urPgne//lib/udev/ata_id': No space left on device
    E: /usr/share/initramfs-tools/hooks/udev failed with return 1.
    update-initramfs: failed for /boot/initrd.img-4.19.0-5-amd64 with 1.
    dpkg: error processing package initramfs-tools (--configure):
     installed initramfs-tools package post-installation script subprocess returned error exit status 1

This commit increases the size of the virtual disk used to build the
image.

Don't inherit $MIRROR from the environment. $mirror gets overridden later
from sourced configuration in conf/dists/*

Don't try to run extlinux

See merge request Librem5/image-builder!157

This does not exist on arm64 and it's not needed.

Explicitly install vmdebootstrap/qemu-user-static on Laniakea Spark instance

See merge request Librem5/image-builder!156

build-image: Exit in case of an unknown dist

See merge request Librem5/image-builder!155

When using the spark builder setup don't carry on if the dist
is unknown.

build-image: Fix spark build condition

See merge request Librem5/image-builder!154

We want to do the setup if SPARK_ID is non-empty

Broken-by: 2db8dc7e

Install unzip in environments where it may be missing

See merge request Librem5/image-builder!108

Add Debian bullseye

See merge request Librem5/image-builder!148

No sshd

See merge request Librem5/image-builder!151

Otherwise we abort image generation due to lack of sshd.

Almost plain builds

See merge request Librem5/image-builder!150

This is supposed to build everything from the archive without
reaching out to external sources. This isn't true for uboot
yet though.

The m4.bin is already fetched in fetch_uboot().

This never worked since the fetched m4.bin is a zip archive
that was never uncompressed.

c2505d88 did only part of the job

Drop mesa from 'patched' check

See merge request Librem5/image-builder!149

Mesa tickled down into pureos-amber and from 19.3 we don't need
patches for basic funtionality anyway so let's drop that check
to make imx6 and qemu images simpler.

root.sh: Make sure we have a all package metadata

See merge request Librem5/image-builder!146

Revert "Make amber-phone images possible right now"

See merge request Librem5/image-builder!147