Add mini web demo

demo/configs/webpack/dev.js

@@ -0,0 +1,19 @@
+// development config
+const { merge } = require("webpack-merge");
+const commonConfig = require("./common");
+
+module.exports = merge(commonConfig, {
+  mode: "development",
+  devServer: {
+    hot: true, // enable HMR on the server
+    open: true,
+    // These headers enable the cross origin isolation state
+    // needed to enable use of SharedArrayBuffer for ONNX 
+    // multithreading. 
+    headers: {
+      "Cross-Origin-Opener-Policy": "same-origin",
+      "Cross-Origin-Embedder-Policy": "credentialless",
+    },
+  },
+  devtool: "cheap-module-source-map",
+});