feat: Webpack 5 support (#1903)

* Upgrade react-dev-utils to latest version v12 (supports Webpack 5)
* Fix Webpack example for local testing
* Upgrade webpack related dependencies for maintenance: webpack, webpack-cli, and webpack-dev-server
* Remove unnecessary Webpack configuration around Hot Module Replacement. webpack-dev-server should automatically inject HMR related configurations already

Closes #1703
Closes #1864
Closes #1740
Closes #1822
Closes #1786

Author: juanca

examples/webpack/package-lock.json

@@ -24,7 +24,7 @@
     "prop-types": "^15.6.1",
     "react": "^17.0.1",
     "react-dom": "^17.0.1",
-    "react-styleguidist": "^11.1.1",
+    "react-styleguidist": "file:../../",
     "style-loader": "^2.0.0",
     "webpack": "^5.3.2"
   },