feat: Payment system with voucher cards.

feat: Design with inversion dependency injection architecture.
feat: Prettier http middleware.
feat: Re-write items categories with preferred accounts.

server/src/services/SMSClient/SMSClientInterface.ts

@@ -0,0 +1,5 @@
+
+export default interface SMSClientInterface {
+  clientName: string;
+  send(to: string, message: string): boolean;
+}