To get more Info about how webpack is configured and second approach to configure webpack with angular you can check out this [BLOG] (https://medium.com/@sahayatanakul2867/configuration-of-webpack4-and-angular-8-using-two-approaches-2bbc4b1cacda).
You can clone this repo for starting point of angular with your own webpack configuration
It uses webpack dev server to run so only required files to run this Project is
| node_modules
| src
| app
| favicon
| index.html
| main.ts
| polyfill.ts
| styles.css
| package.json
| package.lock.json
| tsconfig.json
|Webpack.config.js
you can just clone this repo by
git clone https://github.com/YOUR-USERNAME/Angular8WithWebpack4.git
install node_modules by npm install
run this project by npm run start-dev