Add full media 50 item type, rename full to full media 75, mega full to full media 100.
Use media list 50 for single items in tag containers and article containers
GODDAMMIT INTELLIJ
Merge branch 'master' into less-impactful-single-item-slice
Undo IntelliJ stupidness
Merge pull request #7211 from guardian/less-impactful-single-item-slice

Less impactful single item slice