Draft: Format checker

This is a proof of concept for format checker to include in the CI configuration.

• Violations to the uncrustify configuration file .uncrustify.cfg are reported by the code quality section of gitlab MR:
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• The script will run uncrustify and compare its diff with respect to diff of the target branch and only report the modified ones.

For now, this is a proof of concept. If this idea is promising, the CI configuration files would go to https://gitlab.dune-project.org/core, and the python script to the base image.

The failure of this CI is on purpose, to show that uncrustify only blames commits from this MR.