Make the Video Intro Button Draw Attention to itself if it's the user's first time

[seanahrens]

Frontend Work --- have a tooltip.

Backend Work --- implement something like "current_user.has_seen?(:intro_to_health_data)" which will be the logic to decide whether to highlight it or not.

unsophisticated logic like "is this the user's first session on the site? is insufficient since once the user watches the video/intro its still annoying". a cookie-based implementation could be fine to prevent some backend bloat.