Include more metadata fields in GraphQL query

[mike3985]

This brings the GraphQL version of rendered news articles pages a lot closer to the regular, Content Store version.

I've explained the changes in detail in the commit message. At a high level they're:

• add more fields to query
• update test fixtures to include the new fields

Question: would this benefit from test coverage? I'm happy to add some. I wrote some in the process of making these changes but a few things about them didn't feel quite right so I wanted to check what the general opinion was before proceeding.

https://trello.com/c/HZRt4r50/1666-make-meta-tags-etc-of-graphql-version-of-news-articles-the-same-as-regular-version