Explore more flexible use of macros: What if we only used nested components

[NickColley]

This has come up in some individual examples like:

• Consider making more components callable #941
• when Dave was trying to build the GOV.UK Pay example
• Tables: Consider enabling array iteration in macros #570
• Reveal named div on radio select #718
• Make it clear that the "html" attribute can be unsafe #514
• Make it easier to add a hint or an error message to a fieldset #1281

Do a future thinking SPIKE to see when it'd look like if we encouraged nesting as a default for our macros, what would that look like.

This would give us a better understanding of how we should structure our components in general.

While some recommendations might require breaking changes, I think doing holistic thinking and forwards thinking is good for this kind of issue.

The end of this spike might be:

• simple individual improvements for specific components
  or
• a proposal to simplify large component apis

[NickColley]

Just raising this as it comes up semi-frequently, someone on support wanted to be able to use radios in a more flexible manner.

Will close and add to this when it makes sense to, just wanted to make sure this didn't get lost in the old trello board.