Simplify development environment setup (#1588)

src/Notifications/appsettings.Development.json

@@ -13,6 +13,9 @@
       "internalApi": "http://localhost:4000",
       "internalVault": "http://localhost:4001",
       "internalSso": "http://localhost:51822"
+    },
+    "notifications": {
+      "connectionString": "UseDevelopmentStorage=true"
     }
   }
 }