Merge branch 'feature/ISTWCMS-5633-m26lebla-migrate-header-fix' into '1.0.x'

src/patterns/01-core/mixins/_focus.scss

src/patterns/01-core/mixins/_headings.scss

src/patterns/01-core/mixins/_index.scss

src/patterns/01-core/props/_colors.scss

src/patterns/01-core/props/_sizes.scss

src/patterns/03-layouts/footer/_footer.scss

src/patterns/03-layouts/header/_header.scss

src/patterns/03-layouts/header/header.twig

src/patterns/03-layouts/header/header.yml

src/patterns/03-layouts/layout/_layout-base.scss

src/patterns/03-layouts/layout/_layout.scss

src/patterns/03-layouts/site-container/_site-container.scss

src/patterns/03-layouts/site-footer/_site-footer.scss

src/patterns/04-components/_index.scss

src/patterns/04-components/blockquote/_blockquote.scss

src/patterns/04-components/button/_button.scss

...atterns/04-components/call-to-action/_call-to-action.scss

src/patterns/04-components/card/_card.scss

src/patterns/04-components/card/card--node/_card--node.scss

...tterns/04-components/card/card--teaser/_card--teaser.scss