chore: move next admin packages to core repo (#5983)

**What**
- Move packages for `next` version of admin to core repo

**Other**
- Since this PR introduces packages that depend on Vite 5, it also introduces @types/node@^20. We have never had a direct dependency on the types package for Node, and as far as I can see that has resulted in us using the types from Node.js@8, as those are a dependency of one of our dependencies. With the introduction of @types/node@^20, two of our packages had TS errors because they were using the NodeJS.Timer type, which was deprecated in Node.js@14. We should add specific @types/node packages to all our packages, but I haven't done so in this PR to keep it as clean as possible.
- Q: @olivermrbl I've added the new packages to the ignore list for changeset, is this enough to prevent them from being published?

packages/admin-next/dashboard/src/i18n/config.ts

@@ -0,0 +1,28 @@
+import i18n from "i18next"
+import LanguageDetector from "i18next-browser-languagedetector"
+import Backend, { type HttpBackendOptions } from "i18next-http-backend"
+import { initReactI18next } from "react-i18next"
+
+import { Language } from "./types"
+
+i18n
+  .use(Backend)
+  .use(LanguageDetector)
+  .use(initReactI18next)
+  .init<HttpBackendOptions>({
+    fallbackLng: "en",
+    debug: process.env.NODE_ENV === "development",
+    interpolation: {
+      escapeValue: false,
+    },
+  })
+
+export const languages: Language[] = [
+  {
+    code: "en",
+    display_name: "English",
+    ltr: true,
+  },
+]
+
+export default i18n

packages/admin-next/dashboard/src/i18n/types.ts

@@ -0,0 +1,13 @@
+import en from "../../public/locales/en/translation.json"
+
+const resources = {
+  translation: en,
+} as const
+
+export type Resources = typeof resources
+
+export type Language = {
+  code: string
+  display_name: string
+  ltr: boolean
+}