Use native Wasm+Webpack support for Rust codecs

This delegates loading of Wasm modules to Webpack itself, making wrapper code simpler.

Emscripten-generated modules are still using custom loading glue as they're not compatible with Webpack.

webpack.config.js

@@ -147,8 +147,9 @@ module.exports = async function (_, env) {
           loader: 'exports-loader'
         },
         {
-          // For some reason using `include` here breaks the build.
-          test: /[/\\]codecs[/\\].*\.wasm$/,
+          // Emscripten modules don't work with Webpack's Wasm loader.
+          test: /\.wasm$/,
+          exclude: /_bg\.wasm$/,
           // This is needed to make webpack NOT process wasm files.
           // See https://github.com/webpack/webpack/issues/6725
           type: 'javascript/auto',
@@ -157,6 +158,11 @@ module.exports = async function (_, env) {
             name: '[name].[hash:5].[ext]',
           },
         },
+        {
+          // Wasm modules generated by Rust + wasm-pack work great with Webpack.
+          test: /_bg\.wasm$/,
+          type: 'webassembly/experimental',
+        },
         {
           test: /\.(png|svg|jpg|gif)$/,
           loader: 'file-loader',