remove svelte-i18n dependency, replace with minimalistic implementation

website/src/lib/components/embedding/OpenIn.svelte

@@ -2,7 +2,7 @@
     import { Button } from '$lib/components/ui/button';
     import Logo from '$lib/components/Logo.svelte';
     import { getURLForLanguage } from '$lib/utils';
-    import { _, locale } from 'svelte-i18n';
+    import { _, locale } from '$lib/i18n';
 
     export let files: string[];
     export let ids: string[];