Integrate gitlab-ci/report_image_changes_in_mr

Commit: seco-ne/yocto/infrastructure/gitlab-ci@1299a9d6

CI: add "report-image-diff" job

Add a python script and a GitLab CI job to run it. The job is triggered when the build is complete.

The script retrieves build artifacts for the default/main branch (currently "kirkstone") in the manifest repo and build artifacts for the integration branch of merge request.

After that, it compares those builds and creates a summary of the overall changes. In particular:

• size of compressed artifacts (artifacts.zip)
• size of built image
• difference between manifest files

The summary is reported to stdout and as a comment to the merge request. Each run of the pipeline means removing the old summary comment and creating a new one when the build is finished.

Source merge request: seco-ne/yocto/infrastructure/gitlab-ci!389 (merged)

mentioned in merge request seco-ne/yocto/infrastructure/gitlab-ci!389 (merged)

merged