Be able to distinguish release vs non-release stellar-core packages

[sisuresh]

We had to revert stellar/stellar-core#5183 because it turns out the version string generated for the core packages looks the same for both release and non-release builds. This change was probably made years ago, but we didn't notice in core because it would just emit a warning.

[jacekn]

@sisuresh could you expand a bit on the details here? From the binary build perspective status doesn't matter - we take a commit, version and create an artifact. The artifact is wrapped in a package but also docker image. Ideally a build should be immutable and only be "promoted" through stages. We could try to encode some extra information in the version strings but this will add complexity. Perhaps a better option would be to track build status outside of the version string?