Fundamentals: Product page is kind of weird

**Describe the bug**

https://cyf-curriculum.netlify.app/fundamentals/product/ is kind of weird - it doesn't really have any narrative, or fit into any context... What's it for? Why is it there? I would maybe remove it, or move the content either to the "Context" tab of the root fundamentals page, or a _third_ tab ("Timeline", "Context", and "Product").

It definitely doesn't fit into "Timeline" as a step after sprint 3...

Open the Product page and compare it with the root fundamentals page, especially the Timeline and Context tabs. Decide whether the Product content should be removed, moved into Context, or given its own tab, then verify that the resulting navigation and narrative no longer place Product after sprint 3.

Written by the indexing model from the issue text.