add vscode configuration

Author: ryanhu021

.vscode/extensions.json

@@ -0,0 +1,3 @@
+{
+  "recommendations": ["dbaeumer.vscode-eslint", "esbenp.prettier-vscode"]
+}

.vscode/settings.json

@@ -0,0 +1,7 @@
+{
+  "editor.defaultFormatter": "dbaeumer.vscode-eslint",
+  "editor.formatOnSave": true,
+  "editor.codeActionsOnSave": {
+    "source.fixAll.eslint": "explicit"
+  }
+}