Add FSI courses footer

src/components/i18n/lang/de.json

src/components/i18n/lang/en.json

src/components/pages/ContactPage.tsx

src/components/pages/IndexPage.tsx

src/components/widgets/CreditsFooter.tsx

src/components/widgets/discord/DiscordServerList.tsx

src/components/widgets/discord/generic-disccord-icon.png

src/constants.ts

src/media/logo-ai.png

src/media/logo-info.png

src/media/logo-its.png