Merge branch '5.x' into 5.0.x

.gitignore

README.md

components/accordion-item/accordion-item.component.yml

components/accordion-item/accordion-item.css

components/accordion-item/accordion-item.js

components/accordion-item/accordion-item.scss

components/accordion-item/accordion-item.twig

components/accordion-item/img/accordion-item-border.svg

components/accordion-item/img/icon--book.svg

components/accordion-item/img/icon--circles.svg

components/accordion-item/img/icon--coffee.svg

components/accordion-item/img/icon--concentric-circles.svg

components/accordion-item/img/icon--connections-dark.svg

components/accordion-item/img/icon--connections.svg

components/accordion-item/img/icon--cube.svg

components/accordion-item/img/icon--globe.svg

components/accordion-item/img/icon--group.svg

components/accordion-item/img/icon--hub-dark.svg

components/accordion-item/img/icon--hub.svg

components/accordion-item/img/icon--leader.svg