Cleanup webpack example configs (#606)

* Remove Buffer/process plugins

* Adjust

* Cleanup README

packages/example-react/webpack.config.cjs

@@ -0,0 +1,54 @@
+// Copyright 2017-2022 @polkadot/example-react authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+const path = require('path');
+const { WebpackPluginServe } = require('webpack-plugin-serve');
+
+module.exports = {
+  context: __dirname,
+  devtool: 'eval-cheap-source-map',
+  entry: './src/index.tsx',
+  mode: 'development',
+  module: {
+    rules: [
+      {
+        exclude: /(node_modules)/,
+        test: /\.(ts|tsx)$/,
+        use: [
+          {
+            loader: 'babel-loader',
+            options: require('../../babel.config.cjs')
+          }
+        ]
+      }
+    ]
+  },
+  output: {
+    chunkFilename: '[name].[chunkhash:8].js',
+    filename: '[name].js',
+    globalObject: '(typeof self !== \'undefined\' ? self : this)',
+    path: path.join(__dirname, 'build')
+  },
+  plugins: [
+    new WebpackPluginServe({
+      hmr: false, // switch off, Chrome WASM memory leak
+      liveReload: false, // explict off, overrides hmr
+      port: 8080,
+      progress: false, // since we have hmr off, disable
+      static: __dirname
+    })
+  ],
+  resolve: {
+    alias: {
+      '@polkadot/react-identicon': path.resolve(__dirname, '../react-identicon/build'),
+      '@polkadot/ui-keyring': path.resolve(__dirname, '../ui-keyring/build'),
+      '@polkadot/ui-settings': path.resolve(__dirname, '../ui-settings/build'),
+      '@polkadot/ui-shared': path.resolve(__dirname, '../ui-shared/build'),
+      'react/jsx-runtime': require.resolve('react/jsx-runtime')
+    },
+    extensions: ['.js', '.ts', '.tsx'],
+    fallback: {}
+  },
+  target: 'web',
+  watch: true
+};