Add model packs to variant analyses

[charisk]

Adds modelPacks to variant analysis entities and flows that through from when the packs are discovered to when the entity is created.

The modelPacks property is not persisted yet so it's not mapped over when transforming to query history items. This is intentional - we will change that once we're more confident with the shape of the data. See internal linked issue for details.

Note that this is not used yet, it will be wired up in a follow up PR.

Checklist

N/A:

• CHANGELOG.md has been updated to incorporate all user visible changes made by this pull request.
• Issues have been created for any UI or other user-facing changes made by this pull request.
• [Maintainers only] If this pull request makes user-facing changes that require documentation changes, open a corresponding docs pull request in the github/codeql repo and add the ready-for-doc-review label there.

[shati-patel]

Looks good 🖖🏽

[charisk]

Oops, I got a bit too happy and pressed the merge button, potentially without giving enough people a chance to review. @robertbrignull (and anyone else) please let me know if you have any feedback.