I want to be able to save an artifact generated at a certain revision of the project and move on, not reproducing it later on (freeze, archive, experiment, sample, snapshot)

If the project is naturally experimenting, generating knowledge along the way, but not wanting to reproduce those, we could save, e.g., a figure, along with the git rev at which it was generated, and not keep its creation in the pipeline forever.

```yaml
figures:
- path: figures/plot.png
versions:
v1:
git_rev: 2as5kb5dvdkjfhfhhh55wkjef9f9
description: This was a very good run.
```

We could copy this into `.calkit/archive/figures/figures/plot.png/v1`. That's a little weird. Maybe figures need IDs too. We could also check it out and view it on demand. This could also be a release object.