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>

bin/ci/test/requirements.txt

@@ -0,0 +1,5 @@
+filelock==3.12.4
+fire==0.5.0
+mock==5.1.0
+polars==0.19.3
+pytest==7.4.2