Refactor story package and related content containers to use new facia-container patterns
Refactor styling of discussion header to match new container styles
Refactor Series container to use new facia container pattern
Refactor popular in media container to use new facia pattern
Ensure onward data is correctly type cast
Clean up templates
Fix related content tests
Fix popular in section tests
Fix article feature tests
Fix typo
Refactor FixedContainer class to expose layouts as vals for content containers
Merge pull request #6702 from guardian/content-containers

Content containers (Part 1 of 3)