feat: Implement return and refund functionality in commerce module

- Added return request handling in return.controller.js
- Implemented webhook handling for PayHere payments in webhook.controller.js
- Created models for coupon redemptions, invoices, orders, order items, payments, payment attempts, payment webhook events, refunds, return items, and return requests.
- Developed services for order management, payment processing, refunds, and returns.
- Introduced validation schemas for payment and return requests.
- Created migration scripts for new database tables related to orders, payments, refunds, and returns.
- Added unit tests for order state transitions and PayHere provider functionality.

app/constants/permissions.js

@@ -25,4 +25,5 @@ module.exports = {
   INVENTORY_READ:"inventory.read",INVENTORY_ADJUST:"inventory.adjust",INVENTORY_TRANSFER:"inventory.transfer",INVENTORY_RESERVATIONS_READ:"inventory.reservations.read",INVENTORY_WAREHOUSES_MANAGE:"inventory.warehouses.manage",
   BUSINESS_PRICING_READ:"pricing.business.read",BUSINESS_PRICING_MANAGE:"pricing.business.manage",PROMOTIONS_READ:"promotions.read",PROMOTIONS_MANAGE:"promotions.manage",BANNERS_MANAGE:"merchandising.banners.manage",
   SHIPPING_ZONES_READ:"shipping.zones.read",SHIPPING_ZONES_MANAGE:"shipping.zones.manage",SHIPPING_METHODS_READ:"shipping.methods.read",SHIPPING_METHODS_MANAGE:"shipping.methods.manage",SHIPPING_RATES_READ:"shipping.rates.read",SHIPPING_RATES_MANAGE:"shipping.rates.manage",
+  ORDERS_READ:"orders.read",ORDERS_MANAGE:"orders.manage",ORDERS_CANCEL:"orders.cancel",PAYMENTS_READ:"payments.read",PAYMENTS_MANAGE:"payments.manage",PAYMENTS_REFUND:"payments.refund",INVOICES_READ:"invoices.read",RETURNS_READ:"returns.read",RETURNS_MANAGE:"returns.manage",
 };