chore: added message types to PubSub Service

packages/hoppscotch-backend/src/pubsub/subscriptionTopicsDefs.ts

@@ -0,0 +1,14 @@
+import { UserEnvironment } from '../user-environment/user-environments.model';
+import { PrimitiveTypes } from '../types/primitiveTypes';
+
+// A custom message type that defines the topic and the corresponding payload.
+// For every module that publishes a subscription add its type def and the possible subscription type.
+export type MessageType = {
+  [
+    topic: `user_environment/${string}/${
+      | 'created'
+      | 'updated'
+      | 'deleted'
+      | 'deleted_many'}`
+  ]: UserEnvironment | PrimitiveTypes; // Returning a number hence having a union with `PrimitiveTypes`.
+};