Summary:
Similar to the Hero image functionality. If a video URL is present in the post metadata, it will be displayed instead of a Hero image. This will be useful when highlighting videos in blog posts.
Renamed ReadMoreLink into a more generic ExceptLink which will display "Watch video" when the blog post category is "videos".
Currently there is no way of listing blog posts by categories, but it may be useful to do so later once we have a larger catalog of content.
Closes https://github.com/facebook/react-native/pull/9794
Differential Revision: D3828862
Pulled By: mkonicek
fbshipit-source-id: 1a88aab5edcdf7c84bb679263d6b97d52cf201a2
Summary:
Several blog and sharing improvements are included in this update.
* A larger default preview image is used when a blog post or doc is shared on social media as recommended by [best practices](https://developers.facebook.com/docs/sharing/best-practices#images).
* Follow other Facebook Sharing best practices such as associating the site with a Facebook Page (React) and a Page Admin (121800083 is my fbid, and I am an admin for the React page).
* If the shared blog post contains a hero image, use it as a share preview image.
* Use actual doc content instead of generic site description when sharing docs.
* Update existing hero images to use the larger recommended size.
* Add titles to each author's byline.
* Add author's avatar to their byline.
* Add Twitter Card support.
* Link to individual blog posts from the title and hero image in the blog index.
Old metadata tags (blog post):
```
<meta property="og:title" content="Toward Better Documentation – React Native | A framework for building native
Closes https://github.com/facebook/react-native/pull/9648
Differential Revision: D3790332
Pulled By: hramos
fbshipit-source-id: 4f284c6440482df8a42a2b8467ccf56b1fd725d1
Summary: simple styling change for proper display of the latest blog
Differential Revision: D3748334
fbshipit-source-id: d5d4fceb2396ec05adc3fd3e518e883f78b0c809
Summary: tweaked styling on the latest blog post for better display
Reviewed By: MengjueW
Differential Revision: D3744754
fbshipit-source-id: 4ff16565efd5795319c28cf7044556bfff17a797