Update gitlab CI file to use inherited jobs from main

The .gitlab-ci.yml should be using jobs from a central project in order to facilitate maintainability.

changed milestone to %ETSI Migration Readiness

added statusin progress typeenhancement labels

assigned to @dimit.giannopoulos

added to epic &10 (closed)

created branch 4-update-gitlab-ci-file-to-use-inherited-jobs-from-main to address this issue

mentioned in merge request !3 (merged)

added statusunder review label and removed statusin progress label

removed statusunder review label

closed