build(editor): add VS Code config

Make it easy to initialize the development environment.

.vscode/extensions.json

@@ -0,0 +1,12 @@
+{
+  "recommendations": [
+    // Liquid tags auto-complete
+    "killalau.vscode-liquid-snippets",
+    // Liquid syntax highlighting and formatting
+    "Shopify.theme-check-vscode",
+    // Common formatter
+    "esbenp.prettier-vscode",
+    "foxundermoon.shell-format",
+    "stylelint.vscode-stylelint"
+  ]
+}