Add pbuilder hooks

See merge request Librem5/ansible-librem!14

While at that we also enable lintian and disable manpage generation
to speed up the build.

Allow to build custom chroot

See merge request Librem5/ansible-librem!13

It was manually created before

The armhf and amd64 builds moved to a slave.

This is needed for the custom chroots.

so apt can use them during chroot setup.

Install image build packages on build slaves too

See merge request Librem5/ansible-librem!12

Most of them were there already but not setup via ansible

Good to have for non-local builds

This allows us to have >1 executors on x86 without trying to
build images in parallel.

so we only have to select the hosts to run on.

Do this in a separate infra role that sets up things we might
want on all build related machines.

Until we have moved the builds build on arm01 so we can progress
towards fixing https://code.puri.sm/Librem5/image-builder/issues/50

Can be used like

    bin/aptly-remove-old-versions.py --repo scratch --package-query '$Source (phosh)'
    aptly publish update scratch

to clean out old versions in the scratch/ci repo. Script fetched from

    https://github.com/aptly-dev/aptly/issues/291

with bugfixes on top to fix version detection.

See

    http://honk.sigxcpu.org/projects/git-buildpackage/manual-html/gbp.snapshots.html

This allows us to customize gbp.conf

Now that our

   https://github.com/geerlingguy/ansible-role-jenkins/pull/190

is merged. This unbreaks rollout with ansible 2.5.

Sometimes buster is just not recent enough