Merge pull request #3812 from guardian/remove-postscribe

Postscribe cull
Merge pull request #3784 from guardian/endpoints

Centralised our AWS endpoints.
Trying to add ContentAPI thumbnails to Eventbrite masterclasses.
Refactor series placholder to fragment
Refactor series styling
Merge pull request #3814 from guardian/healthchecks

Healthchecks now identify themselves with a header
using eval to run breakout swcript
Merge pull request #3815 from guardian/commercial-component-fix

Commercial: using eval to run breakout script
Refactor ad targeting

So that same targeting can be applied to video ads.
commercial styling and html for masterclasses
Add commercial component slot to front
missing quote
Refactor video ad targeting

So that uses same targeting as that applied to standard ads.
Refactor querystring building
adding integration tests
Clean up series labelling
Merge pull request #3816 from guardian/commercial-component-fronts

Commercial: add component slot to front
Merge pull request #3809 from guardian/commercial-switch-logic

Commercial: correct advert switch logic
Improved alert messages
commercial, html & css for masterclasses