gitlab-ci: Build package
gitlab-ci: Build package

We unfortunately can't use salsa-ci's prebuilt pipeline since
that hangs on large jobs:
https://salsa.debian.org/salsa/support/issues/180

We redirct output to a file to work around:
https://salsa.debian.org/salsa/support/issues/191

agx/libvirt-debian,agx/libvirt-debian,agx/libvirt-debian,agx/libvirt-debian,agx/libvirt-debian