Prevent overwriting current CI Docker image in CI build
Currently it's too easy to change the CI Dockerfile and cause it to overwrite the tag in the registry, with potential catastrophic effects for other jobs. Since we don't yet have tag immutability, we need a poor-man's alternative for it.
- create a script that would create the suffix as hash from the
dockerfiles/ci/directory content and update the
CI_IMAGEvalues in the yaml files.
- extend the build ci image job to re-execute the script and check if the
CI_IMAGEvalue equals what was computed locally. If not - fail the job.