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>