Add link unfurl query to GraphQL API
Created by: tjkandala
Closes #15735 (onboarding task for @vdavid).
TODO
-
Add query to GraphQL schema -
Make HTTP request for URL -
Parse HTML and return relevant meta tags -
Follow redirects when making a request to the URL -
Add tests -
Add caching
This endpoint will be used by the link-preview-expander Sourcegraph extension.