"Advanced" example of sliding on an archive that isn't forecasting

* The [place](https://github.com/cmu-delphi/delphi-tooling-book/blob/6f7a0b14bf5d892472acf1c73a26d207df9657c0/archive.qmd#L245) where it would be helpful. 
* The [deployment](https://cmu-delphi.github.io/delphi-tooling-book/archive.html#sliding-version-aware-computations)
* I think we could eventually expand to an entire chapter with multiple examples.





