Build and release binary for s390x

What does this MR do?

Adds binary compilation and release for IBM mainframes - linux/s390x.

• Example release index: https://gitlab-runner-downloads.s3.amazonaws.com/binary-zos/index.html
• Example artifacts: https://gitlab.com/gitlab-org/gitlab-runner/-/jobs/587736358/artifacts/browse/out/binaries/

Why was this MR needed?

Are there points in the code the reviewer needs to double check?

Does this MR meet the acceptance criteria?

• Documentation created/updated
• Added tests for this feature/bug
• In case of conflicts with master - branch was rebased

What are the relevant issue numbers?

Closes #25794 (closed)