additional css for presentation layer of menu and addition of site name to header

css/styles.css

js/component_scripts.min.js

source/_patterns/03-layouts/content/_content.scss

source/_patterns/03-layouts/content/content.twig

source/_patterns/03-layouts/header/_header.scss

source/_patterns/03-layouts/header/header.twig

...s/04-components/menu/menu--horizontal/menu--horizontal.js

...ns/04-components/menu/menu--secondary/menu--secondary.yml

source/_patterns/04-components/site-name/_site-name.scss

source/_patterns/04-components/site-name/site-name.twig