[sagittaire] Put sagittaire 17 & 18 to retired.
Also remove last traces of sagittaire-19.
GitLab upgrade completed. Current version is 17.10.3. We now benefit from the enhancements of 17.9 and 17.10 releases. Among other improvements, it is now possible to set the automatic deletion of continuous integration pipelines. You can help us reduce storage usage by setting an expiry date for your pipelines.
Also remove last traces of sagittaire-19.