DO NOT MERGE. Basic page changes

4 things. This:
- slims down basic page (in response to not many people getting to the end of the page)
- introduces a small but prominent mention of the basic API
- moves video to the top of the page
- adds a customer story banner

This is dependent on a few up and coming changes to the branch, so do not merge.
Looking to deploy this afternoon, but each new aspect separately as A/B test. This PR shows the finished version with all changes implemented simultaneously.

@anothertompetty or @almonk would really appreciate a review and any recommendations before 2:30pm if possible.
The testimonial should be nested within this `id` — it will make sure that the page nav says 'overview' whilst scrolling over it