Inline CSS & JS into HTML export template

Previously, the HTML export template `html.hbs` included CDN links
for the HTML and CSS resources.

This commit enables Webpack to create a new `htmlexport.html` at
build-time, which includes all resources inline.
That template is then used as before by the frontend to be populated
with the rendered note content.

The tradeoff is that each exported .html file is about 5.6 MB in size,
as we need to inline all fonts (icons & emojis).

Signed-off-by: David Mehren <git@herrmehren.de>

webpack.htmlexport.js

@@ -1,5 +1,6 @@
 const MiniCssExtractPlugin = require('mini-css-extract-plugin')
 const path = require('path')
+const HtmlWebpackPlugin = require('html-webpack-plugin')
 
 module.exports = {
   name: 'save-as-html',
@@ -10,6 +11,14 @@ module.exports = {
     rules: [{
       test: /\.css$/,
       use: [MiniCssExtractPlugin.loader, 'css-loader']
+    },
+    {
+      test: /\.(woff(2)?|ttf|eot|svg)(\?v=\d+\.\d+\.\d+)?$/,
+      use: [
+        {
+          loader: 'url-loader'
+        }
+      ]
     }]
   },
   output: {
@@ -18,8 +27,13 @@ module.exports = {
     filename: '[name].js'
   },
   plugins: [
-    new MiniCssExtractPlugin({
-      filename: 'html.min.css'
-    })
+    new HtmlWebpackPlugin({
+      // Load a custom template (uses lodash templating)
+      template: 'public/views/htmlexport.ejs',
+      filename: 'htmlexport.html',
+      inject: false,
+      cache: false
+    }),
+    new MiniCssExtractPlugin({ filename: 'htmlexport.css' })
   ]
 }