Upmerge of latest meta-zephyr kirkstone branch without the new CI

In general a normal upmerge of the latest changes in upstream meta-zephyr kirkstone branch.

The tricky part is that upstream now also uses Gitlab CI pipeline and the configuration files conflicts with our downstream CI. In lack of better options we remove the upstream files here and need to maintain this going forward. Which means we need to handle the merge conflicts which will result from this for each upmerge.