Update frontend build system to shed old dependencies, and address fallout from that (#521)

* get tests working and update copyright headers

* lint fix

* eslint ts update

* update CI to use NPM

* fix CI

* prettier

* npm, not yarn for docker

* remove unused package

* bump dockerfile to latest node LTS and no need for cache clean

* make frontend Dockerfile work and remove unused SUBSTRATE_TELEMETRY_SAMPLE

* remove final yarn references

* add another comment

* remove unused import

* remove more unused deps

* comment typo

frontend/webpack.config.js

@@ -0,0 +1,51 @@
+const path = require('path');
+const HtmlWebpackPlugin = require('html-webpack-plugin');
+
+module.exports = {
+  entry: './src/index.tsx',
+  devtool: 'inline-source-map',
+  module: {
+    rules: [
+      {
+        // Allow 'import * from "./foo.tsx"'
+        test: /\.tsx?$/,
+        use: 'ts-loader',
+        exclude: /node_modules/,
+      },
+      {
+        // allow 'import "foo.css"' and '@import "foo.css" in css files
+        test: /\.css$/i,
+        use: ['style-loader', 'css-loader'],
+        generator: { filename: 'styles/[name].[contenthash][ext]' }
+      },
+      {
+        // allow 'import Icon from "./icon.png"'
+        test: /\.(png|svg|jpg|jpeg|gif)$/i,
+        type: 'asset/resource',
+        generator: { filename: 'images/[name].[contenthash][ext]' }
+      },
+      {
+        // allow CSS @url('./my-font.woff2')" style font loading
+        test: /\.(woff|woff2|eot|ttf|otf)$/i,
+        type: 'asset/resource',
+        generator: { filename: 'fonts/[name].[contenthash][ext]' }
+      },
+    ],
+  },
+  plugins: [
+    // Use our index.html as a starting point (to add script links etc to)
+    // and make sure to use/copy over the favicon too.
+    new HtmlWebpackPlugin({
+      favicon: "./assets/favicon.svg",
+      template:  "./assets/index.html"
+    }),
+  ],
+  resolve: {
+    extensions: ['.tsx', '.ts', '.js'],
+  },
+  output: {
+    filename: 'main.[contenthash].js',
+    path: path.resolve(__dirname, 'build'),
+    clean: true
+  },
+};