* Simplify social images and add ability to set per-page images
- Removes the homepage summary layout in favor of the larger image card (makes it more consistent with other pages)
- Reuses new thumbnails for Webpack, Parcel, and Vite guides to add their new social images
* Update default social card
* Change description to subtitle, add longer description to match homepage
* Remove social_image_path, use inline conditions for social images
