Deploy formatting updates to production

This deploys some things to production:

* Adds a link to the left of all blog posts that goes back to `/news`/.
* Adds a tag to the EITI blog post.
* Replaces protocol-relative links with `https://` links.
* Adds support for syntax highlighting in blog posts using GitHub-style fenced code blocks.
* Rejiggers `<!-- more -->` separators to be on their own line in all cases (changes the excerpt for a few blog posts).