[FEAT] Daffodil Design Package Link should link to /docs/design

[damienwebdev]

1. The link: https://next.daff.io/docs/packages/design should navigate you to /docs/design
2. The @daffodil/design tree item in the sidebar on the package list should not be a tree item with children, it should just be a top-level element.
3. The @daffodil/design tree item in the sidebar on the package should be a link to /docs/design.