Integrate gitlab-ci/make-check-error-more-verbose and 5 more

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Commit: seco-ne/yocto/infrastructure/gitlab-ci@f8d6de86

Make check error message more verbose

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Commit: seco-ne/yocto/infrastructure/gitlab-ci@21e7edeb

Improve ci-test build

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Commit: seco-ne/yocto/infrastructure/gitlab-ci@76bd81d8

Fix check job rules

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Commit: seco-ne/yocto/infrastructure/gitlab-ci@a6721243

Move check job to parent pipeline

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Commit: seco-ne/yocto/infrastructure/gitlab-ci@593784e1

Refactor check_if_integration_branch_is_up_to_date

- Use "source" and "target" terminology in the script, just like in the
  GitLab CI variables.
- Spefify data types for function arguments.
- Rename function arguments to better reflect their data types.
- Move determination of integration branch into main function, so that
  the successfull status message can be more verbose.
- Remove parent_merge_request feature and checking for gitlab-ci
  integrations, because the check job does not run on gitlab-ci
  integration branches at all.

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Commit: seco-ne/yocto/infrastructure/gitlab-ci@45b49ee3

Remove build stage on master

We don't need to explicitly trigger a build after merging changes in
gitlab-ci. A master pipeline on the target projects runs automatically.