gitlab-ci: Parametrize the osname and handle authenticated access

Make the downstreams' life easier by making the osname a parameter that can be easily customized instead of hardcoding apertis in multiple places.

When retrieving the artifacts, pass the job token so that things work fine even for downstreams requiring authenticated access.

.gitlab-ci.yml

+variables:
+  osname: apertis
+  release: v2021
+  STABLE_BRANCHES: v2019 v2020 v2021
+  DEV_BRANCHES: v2022dev2 v2022dev3 v2022pre v2023dev0
+
 .render:
-  image: registry.gitlab.apertis.org/infrastructure/apertis-docker-images/v2022dev0-testcases-builder
+  image: ${CI_REGISTRY}/infrastructure/${osname}-docker-images/${release}-testcases-builder
   stage: deploy
   tags:
     - lightweight
   script:
     - mkdir public
-    - STABLE_BRANCHES="v2019 v2020 v2021"
-    - DEV_BRANCHES="v2022dev2 v2022dev3 v2022pre v2023dev0"
-    - for BRANCH in $STABLE_BRANCHES $DEV_BRANCHES; do
-    -   echo "Retrieving archive for $BRANCH"
-    -   curl --fail --location --output $BRANCH.zip "https://gitlab.apertis.org/tests/apertis-test-cases/-/jobs/artifacts/apertis/$BRANCH/download?job=render-pages" && unzip -d public $BRANCH.zip || true
-    - done
+    - |
+      set -x
+      for BRANCH in $STABLE_BRANCHES $DEV_BRANCHES; do
+        echo "Retrieving archive for $BRANCH"
+        URL=$CI_API_V4_URL/projects/tests%2Fapertis-test-cases/jobs/artifacts/${osname}%2F${BRANCH}/download?job=render-pages
+        curl --header "JOB-TOKEN: $CI_JOB_TOKEN" --fail --location --output $BRANCH.zip "$URL" && unzip -d public $BRANCH.zip || true
+      done
+      set +x
     - cp static/* public/
     - ./atc_menu -o ./public/ public/
     - ln -s $BRANCH public/latest