Support viewing AEPs as of a date (for snapshots and slug transfer)

[rofrankel]

Just recording a half-baked idea for how we might support versions/snapshots and transferable slugs.

Each AEP already has a creation date. If I want to view a snapshot of the AEPs as of some date, we can use the following logic:

• When the as-of date isn't specified, it defaults to today.
• Don't show AEPs created after the as-of date.
• Resolve slugs to the youngest AEP created before the as-of date with that slug.
• Don't take slugs away from AEPs when creating new AEPs with the same slug.

Implications:

• Slugs are not unique, just {slug, creation date} pairs.
• This wouldn't support true snapshots, because in-place updates to an AEP after the as-of date would show up if a new AEP hasn't been created. However, I think this is fine given the idea that breaking changes to an AEP should result in the creation of a new AEP (because then any updates from after the as-of date are non-breaking, and so should not affect compliance).

Thoughts?

[rambleraptor]

We could extend this generator with a list of static dates.

If we want users to pick an arbitrary date, we'll have to introduce a server to our static webpage or migrate to a single-page architecture. Either of those would be a big migration.