[chore] Introduce HTML-Webpack

This issue means that any changes to the HTML has to happen in the
`.\src\index.html` file rather than the `.\index.html`. This makes the
`index.html` in the root now a build artifact the same way that files in
`dist\` are.

package.json

@@ -45,6 +45,7 @@
     "eslint": "^4.19.1",
     "eslint-plugin-node": "^6.0.1",
     "file-loader": "^1.1.11",
+    "html-webpack-plugin": "^3.2.0",
     "i18n-webpack-plugin": "^1.0.0",
     "istanbul": "^0.4.5",
     "js-beautify": "^1.5.10",