feat: Add the basic implementation of notification module (#7282)

* feat: Add the basic implementation of notification module

* fix: Minor fixes and introduction of idempotency key

* fix: Changes based on PR review

packages/core/utils/src/notification/abstract-notification-provider.ts

@@ -0,0 +1,15 @@
+import { NotificationTypes, INotificationProvider } from "@medusajs/types"
+
+export class AbstractNotificationProviderService
+  implements INotificationProvider
+{
+  async send(
+    notification: NotificationTypes.ProviderSendNotificationDTO
+  ): Promise<NotificationTypes.ProviderSendNotificationResultsDTO> {
+    throw Error(
+      `send is not implemented in ${
+        Object.getPrototypeOf(this).constructor.name
+      }`
+    )
+  }
+}

packages/core/utils/src/notification/index.ts

@@ -0,0 +1 @@
+export * from "./abstract-notification-provider"