Add steps per instruction page

[cocomarine]

Story: https://github.com/RaspberryPiFoundation/digital-code-club/issues/1057

Project markdown Figjam: https://www.figma.com/board/4V3lzgpGUFpiuqd8hLWVJM/Project-markdown-comparisons?node-id=0-1&p=f&t=ftZcKXaLRIK2LFBM-0

Description

For this, Marc's team will use h3 elements (###) in markdown and manually write out "step 1, step 2, step 3".
However, we need to implement this without impacting on other h3 elements.

Build notes

• Style it as per design
• Make sure it doesn’t impact any other h3 elements on the page as well as other products' editors.
  • Can we wrap the instructions panel in CCP specific div and style there?
  • Or can we use WC's part attributes to specify CCP specific styling? (https://github.com/RaspberryPiFoundation/editor-ui?tab=readme-ov-file#styling-externally)
• Make sure Tip + Debugging boxes work ok
• Make sure the existing pages don't look terrible

Important documents

Document	Link
Designs	https://www.figma.com/design/2XzRDyXtthyzeNMZtdChTQ/Projects-site---Designs?node-id=10782-15721&m=dev