Support CI workflow with specified ROM, FMC, and RT versions

[jhand2]

Revisions of ROM and FMC/RT are spread across different branches/tags. We do not currently have a way to produce a single release which will package binaries at specific revisions (currently our release builds everything from a single commit).

We should be able to build FMC/RT from head, but still bundle ROM for a specific release (e.g. 1.0.1).

This can be a Github workflow which takes as input parameters specific tags/commit hashes at which to build each firmware stage.

[benjamindoron]

At the moment, we can't build FMC and RT separately: the builder does all of this, then creates the image bundle.

• We could enhance the builder to also support generating a bundle from an FMC and RT ELF

The current plan is to create a new workflow that takes ROM and FW git refs as parameters, and:

• Execute tests: Pass these in to the FPGA and sw-emulator tests. These will now build twice, and copy in the ROM ELF tests as overrides to a destination folder for cargo-nextest to consume.
  • Progress: Done, but many tests still build their own ROM. We need to refactor them to optionally consume a ROM from, for example, a path in an environment variable.
• Build release: Pass these into build_release.sh
  • Progress: Done. But we note that it's fragile, because some paths have moved over the course of releases. For example hw-latest/ to hw/latest/. We might address this in rom-1.0 by symlinking the old path over to the new one. But this will not fix it for any possible git ref.