History of Advisories

Right now, when an advisory is updated upstream, we create a new record in the db(mark it with `is_latest=True`) on the subsequent importer run but there is no way for a user to see ***`what`*** actually changed over time.

- At first we need a `Way Back Machine` mimic for advisories to see a advisory snapshot exactly how it was at that point in time
- We display the diffs between versions directly in the UI (if a severity score changes, a new reference is added, or a package is removed, users should be able to see exactly when and what happened at a glance)

**Suggested UX:**
- Add a "History" tab to the advisory detail page.
- Show a chronologically ordered list of versions of the advisory
- Allow users to click into a specific historical snapshot to view the advisory exactly as it was at that point in time, just like a way Back Machine
- Need a summary/diff of what changed for a quick overview

Excluding changes summary and epss score(can be tracked after merge of https://github.com/aboutcode-org/vulnerablecode/pull/2328 ; also since it changes everyday) might be good.