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/interfaces/Payment.ts

@@ -0,0 +1,20 @@
+
+
+export interface IPaymentModel {}
+
+export interface IVoucherPaymentModel extends IPaymentModel {
+  voucherCode: string;
+}
+
+export interface IPaymentMethod {
+  makePayment(paymentModel: IPaymentModel): Promise<boolean>;
+}
+
+export interface IVoucherPaymentMethod {
+  makePayment(paymentModel: IVoucherPaymentModel): Promise<boolean>;
+}
+
+export interface IPaymentContext<PaymentModel> {
+  paymentMethod: IPaymentMethod;
+  makePayment(paymentModel: PaymentModel): Promise<boolean>;
+}