Track expanded state of db items

[charisk]

Adds logic to track expanded state for db items:

• Adds an expanded property in the db config, which contains an array of items that are expanded
• Adds an expanded property on some kinds of db items
• Updates to db item creation to look at the expanded property in the db config and set the db item's expanded property where appropriate.
• Adds expanded to a lot of test data

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.