Create `ArticleDesign.HostedGallery` `ArticleDesign.HostedArticle` and `ArticleDesign.HostedVideo`

These are very different from regular editorial content and should have their own `ArticleDesign`:

- https://www.theguardian.com/advertiser-content/special-places-to-stay/the-uks-most-beautiful-foodie-pubs-with-rooms
- https://www.theguardian.com/advertiser-content/we-are-still-in/faces-of-we-are-still-in
- https://www.theguardian.com/advertiser-content/new-york-tourism-ilny/heritage-and-art-combine-on-a-cultural-journey-across-new-york-state

Once we have a separate `ArticleDesign`, these should be excluded from the galleries migration and treated as a separate task.