ISTWCMS-5596: import of initial base element css and patterns

src/patterns/01-core/elements/_blockquote.scss

src/patterns/01-core/elements/_body.scss

src/patterns/01-core/elements/_definition-list.scss

src/patterns/01-core/elements/_details.scss

src/patterns/01-core/elements/_fieldset.scss

src/patterns/01-core/elements/_figure.scss

src/patterns/01-core/elements/_form.scss

src/patterns/01-core/elements/_html.scss

src/patterns/01-core/elements/_label.scss

src/patterns/01-core/elements/_option.scss

src/patterns/01-core/elements/_paragraph.scss

src/patterns/01-core/elements/_textarea.scss

src/patterns/01-core/font-face/_index.scss

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

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

src/patterns/04-components/_index.scss

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

src/patterns/04-components/blockquote/blockquote.twig

src/patterns/04-components/blockquote/blockquote.yml

src/patterns/04-components/fieldset/fieldset.twig