Remove Content page example (#121)

This example page has a selection of content components on it. However it’s not linked to from anywhere and is an orphaned page.

I’m not sure it has much value, as all of the components are available separately on the Design System website (where there’s also guidance on when to use them).

Screenshot for posterity:

![page-example](https://github.com/user-attachments/assets/9dee6e0a-6b26-40f0-b411-5bc53e5acc85)