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/modules/notification/tsconfig.spec.json

@@ -0,0 +1,8 @@
+{
+  "extends": "./tsconfig.json",
+  "include": ["src", "integration-tests"],
+  "exclude": ["node_modules", "dist"],
+  "compilerOptions": {
+    "sourceMap": true
+  }
+}