Add some scaffold for related links

I'm assuming here that these will come from the API, guessing at the interface here a bit.
Add css for related links

- Remove unnecessary h1 styling behind media query.
- Add css for related links, collapsing them down and to the left for mobile
Add HTML for related links
CSS fixes for related links

- Remove position:relative so links are clickable as the metadata doesn't sit above them
- Add padding for links
Remove dummy code, wire in artefact api result

Replace dummy stand in code with real stuff. I didn't realise it would be this easy or I would have done it to begin with!
Merge pull request #62 from alphagov/styling-for-related-links

Styling for related links