Extend the debian-pipeline workflow to hook with the package_publish workflow

We want to be able to create debian_pipeline workflows where the built packages end up installed in a debian:suite collection with the help of the package_publish sub-workflow. So we need to extend the debian_pipeline workflow to support this.

This is a required step to be able to upload packages into Debusine managed package repositories.

Initial issue description

**Original title: Extend the debian-pipeline workflow to install packages in a debian:suite collection**

The debian-pipeline design left this as a "todo" for the future but it would be helpful if we could install built packages in a debian:suite collection even before we have package repositories in debusine.

The reason is that debian:suite collections can be configured to retain all historical artifacts and we want this feature in the context of ELTS. With the current reprepro setup, once a package has been replaced by a newer version, the former version is lost. But it's helpful for ELTS contributors to be able to inspect historical uploads. And it's helpful for customers to be able to retrieve the former version when a regression has been introduced in the current version.

Note that this "snapshot" service can also be obtained by mirroring the ELTS repositories inside debusine so I'm not scheduling this issue for now as we have a suitable work-around.