ISTWCMS-5881: css to change icon presentation, social icon now using inline svg

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

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

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

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

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

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

src/patterns/03-layouts/site-container/site-container.yml

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

src/patterns/03-layouts/site-footer/site-footer.twig

src/patterns/03-layouts/site-footer/site-footer.yml

src/patterns/04-components/_index.scss

src/patterns/04-components/icon/_icon.scss

...tterns/04-components/icon/icon--button/_icon--button.scss

src/patterns/04-components/links/_links.scss

...tterns/04-components/menu/menu--footer/_menu--footer.scss

...tterns/04-components/menu/menu--social/_menu--social.scss

...atterns/04-components/menu/menu--social/menu--social.twig

...patterns/04-components/menu/menu--social/menu--social.yml

.../social-media/social-media--icon/_social-media--icon.scss

...s/social-media/social-media--icon/social-media--icon.twig