Add tRPC, use it for group expenses, balances and information page (#246)

* Add tRPC, use it for group expense list

* Use tRPC for balances

* Use tRPC in group information + better loading states

src/trpc/init.ts

@@ -0,0 +1,25 @@
+import { initTRPC } from '@trpc/server'
+import { cache } from 'react'
+import superjson from 'superjson'
+
+export const createTRPCContext = cache(async () => {
+  /**
+   * @see: https://trpc.io/docs/server/context
+   */
+  return {}
+})
+
+// Avoid exporting the entire t-object
+// since it's not very descriptive.
+// For instance, the use of a t variable
+// is common in i18n libraries.
+const t = initTRPC.create({
+  /**
+   * @see https://trpc.io/docs/server/data-transformers
+   */
+  transformer: superjson,
+})
+
+// Base router and procedure helpers
+export const createTRPCRouter = t.router
+export const baseProcedure = t.procedure