Rails backend SLSA attestation generation POC
The goal of this POC is to ensure that the direction discussed in Architectural Decision: Where do we generate SL... (#537049 - closed) is achievable.
The expectation is that it will be possible to accomplish attestation generation via the Rails backend and achieve feature parity with https://docs.gitlab.com/ci/runners/configure_runners/#artifact-provenance-metadata
This POC will be successful when it can be proven that the exact same output can be generated from both mechanisms (Rails & Runner).