Refactor component READMEs & macros

[chrimesdev]

We need to refactor each of the component READMEs and macros to make sure they are consistent. There is a new README template to use across all components.

• Make sure each of the component READMEs are consistent with each other.

• Each component has a GitHub issue and is linked to from the README.

• Make sure each of the parameters are consistent with each other.

• Make sure each of the macros can pass classes and attributes.

• Create a table of macro arguments for each component

• Decide on a policy on our advice to using macros due to the security risk https://mozilla.github.io/nunjucks/api.html#user-defined-templates-warning

• [x] Action link

• [x] Breadcrumb

• [x] Primary Care Card

• [x] Emergency Care Card

• [x] Urgent Care Card

• [x] Contents list

• [x] Details

• [x] Do and Don't list

• [ ] Emergency alert

• [ ] Expander

• [ ] Expander group

• [ ] Feedback banner

• [ ] Footer

• [ ] Header

• [ ] Header transactional

• [ ] Header with navigation

• [ ] Header with search

• [ ] Hero

• [ ] Hero with image

• [ ] Hero with image with content

• [ ] Images

• [ ] Inset text

• [ ] List panel

• [ ] Pagination

• [ ] Panel

• [ ] Panel with grey background

• [ ] Panel with label

• [ ] Promo

• [ ] Promo with no description

• [ ] Promo small

• [ ] Promo with image

• [ ] Review date

• [ ] Skip link

• [ ] Tables

• [ ] Warning callout

[mikemonteith]

READMEs are actually being built into the github-pages docs, but they're not linked to yet.

https://nhsuk.github.io/nhsuk-frontend/components/care-card/README.html