ci/bin: Add script to expand jobs manifest

ci/bin: Add script to expand jobs manifest

Normally, Mesa devs bump into CI errors and need to replicate the CI job
environment locally, but that is not an easy task, since one needs to
find the merged YAML CI file from Gitlab interface.

As it can happen often, here is a script that use Gitlab's GraphQL and
finds all the variables set by it, alongside with the container image
used to run it and the script that it will run.

Signed-off-by: Guilherme Gallo <guilherme.gallo@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17791>