make trpc-nuxt flexible by exporting server and client functions instead of nuxt modules

playground/server/api/trpc/[trpc].ts

@@ -0,0 +1,12 @@
+import { createNuxtApiHandler } from 'trpc-nuxt'
+import { appRouter } from '../../trpc/routers'
+
+export default createNuxtApiHandler({
+  router: appRouter,
+  createContext: async () => {
+    return {}
+  },
+  onError({ error }) {
+    console.log('Error', error)
+  },
+})