Add new tool: routine-update-apertis

This tool, inspired by https://tracker.debian.org/pkg/routine-update

,
performs common cleanups in Apertis packages like:
   - remove deprecated debian/apertis/gitlab-ci.yml
   - add debian/apertis/lintian for packages maintained by Apertis

Signed-off-by: Dylan Aïssi <dylan.aissi@collabora.com>