Add a question page example

[vickytnz]

What

Add an example of a question page like the GOV.UK one https://design-system.service.gov.uk/patterns/question-pages/

Why

At present it's hard to figure out how to code a default page for example:

• where to place multiple elements like the continue button
• if the back link is 'back' or 'go back' (since there is inconsistency between the design system, prototype kit, and app design system)
• if the typography is correct (to me the spacing looks odd but it appears that this is what the default looks like)

The prototype kit has some examples but hidden in document files and potentially out of date. The design system is the better point of truth.

Having some examples would create an easy baseline, as well as highlight if there is a chance to review the styles as they are.