Merge branch 'header-behaviour' into 'development'

src/components.d.ts

src/components/navigation/menu-item/menu-item.scss

src/components/navigation/menu-item/readme.md

src/components/navigation/menu-language/menu-language.scss

src/components/navigation/menu-language/menu-language.tsx

...navigation/menu-level-container/menu-level-container.scss

src/components/navigation/menu-level-container/readme.md

src/components/navigation/menu/menu.scss

src/components/navigation/menu/readme.md

src/components/site-header/readme.md

src/components/site-header/site-header.scss

src/components/site-header/site-header.tsx

src/components/site-header/site-logo/site-logo.scss

src/components/site-header/site-logo/site-logo.tsx

src/components/site-header/site-search/site-search.scss

src/components/site-header/site-search/site-search.tsx

src/index.html

src/utils/utils.ts