Contentful: Split entries into types story / page / report (for now).

[rin]

This is for existing entries. Split them into page (for Terms and Conditions), reports (for … reports!) and stories.
Needs changes to contentful and then also in code. (First bring the content model changes to the master environment, because it won't break anything, then change the code to use these content types instead of content tags.)

Bonus: Documentation needs to be updated.