Create .vscode/launch.json

It defines the possible debug targets available in Visual Studio Code (-based) editors, as specified here:
https://code.visualstudio.com/docs/nodejs/nodejs-debugging

The specified configuration allows the debugging of the webpack development server launched with `npm run start`.

.vscode/launch.json

@@ -0,0 +1,17 @@
+{
+    "configurations": [
+        {
+            "type": "node",
+            "name": "start",
+            "request": "launch",
+            "runtimeExecutable": "npm",
+            "runtimeArgs": [
+                "run-script",
+                "start"
+            ],
+            "skipFiles": [
+                "<node_internals>/**"
+            ]
+        }
+    ]
+}