ci: bare-metal: poe: Create strutured logs

Use the CustomLogger class and CLI tool to create strutured logs
for poe scripts which are used by broadcom and nouveau jobs.
Renamed stage lint to code-validation and added python-test job
which runs the tests for structured and customer logger to ci.

Signed-off-by: Vignesh Raman <vignesh.raman@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25179>

.gitlab-ci.yml

@@ -85,6 +85,8 @@ variables:
   # Re-enable farm with `git mv .ci-farms{-disabled,}/$farm_name`
   # NEVER MIX FARM MAINTENANCE WITH ANY OTHER CHANGE IN THE SAME MERGE REQUEST!
   ARTIFACTS_BASE_URL: https://${CI_PROJECT_ROOT_NAMESPACE}.${CI_PAGES_DOMAIN}/-/${CI_PROJECT_NAME}/-/jobs/${CI_JOB_ID}/artifacts
+  # Python scripts for structured logger
+  PYTHONPATH: "$PYTHONPATH:$CI_PROJECT_DIR/install"
 
 default:
   before_script:
@@ -127,7 +129,7 @@ stages:
   - git-archive
   - build-x86_64
   - build-misc
-  - lint
+  - code-validation
   - amd
   - intel
   - nouveau