Add more hero images

hugo/content/anleitung.md

hugo/content/datenschutz.md

hugo/content/funktion.md

hugo/content/impressum.md

hugo/content/quellen.md

hugo/content/veranstaltungen.md

hugo/layouts/_default/single.html

hugo/layouts/partials/hero.html

hugo/static/hero.jpg

hugo/static/heroes/anleitung-fabi.jpg

hugo/static/heroes/boxen-fabi.jpg

hugo/static/heroes/loeten-fabi.jpg

hugo/static/heroes/messen-fabi.jpg

hugo/static/heroes/nook-malte.jpg

hugo/static/heroes/oszi-leo.jpg

hugo/static/heroes/platine-fabi.jpg