WIP: Initial Jenkinsfile configuration

This is just a Proof-Of-Concept implementation to move the current manual jobs in Jenkins to pipeline jobs that can be versioned controlled in Jenkinsfile. I have reorganized a bit the jobs, and merged dsc, binary and publish into a single pipeline. Regarding the gitlab jobs, it would probably make sense to merge gitlab-commit and gitlab-merge-request into a single pipeline job and to actually place it in the package-helpers repo.

Here some screenshots of how it would look like.