Improve Salsa CI

Description of the project: Salsa CI is a Continuous Integration tool set built upon the Debian GitLab instance (Salsa). It provides a pipeline that helps maintainers to ensure a robust development cycle by continuously checking the health of Debian packages before they are uploaded to the archive. Other than checking if the packages build on a clean Debian environment (on amd64 and i386 for now), the Salsa CI Pipeline runs a set of jobs that make use of different tools related to the development of Debian to test different aspects of the packages. After three years of development, the Salsa CI pipeline has become popular (used by ~8k projects, from mariadb to the linux kernel packaging), and it is even the base for more complex CI pipelines used by other Linux flavours (such as Kali Linux or the Continuous Delivery at ALBA synchrotron). There are however different bugs that we would like to solve, whose list could be defined with the interested intern.