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/admin-bundler/src/api/dev.ts

@@ -0,0 +1,28 @@
+import { createServer } from "vite"
+// @ts-ignore
+import { createViteConfig } from "./create-vite-config"
+
+type DevArgs = {
+  port?: number | undefined
+  host?: string | boolean | undefined
+}
+
+export async function dev({ port = 5173, host }: DevArgs) {
+  const config = await createViteConfig({
+    server: {
+      port,
+      host,
+    },
+  })
+
+  if (!config) {
+    return
+  }
+
+  const server = await createServer(config)
+
+  await server.listen()
+
+  server.printUrls()
+  server.bindCLIShortcuts({ print: true })
+}