MM-52536 Webpack unification part 1 (#23322)

* MM-52536 Update Webpack and use the same version for all products

* Switch Channels to use asset modules

* Remove unused module configuration from Boards/Playbooks

* Remove file-loader and html-loader

* Unify versions of CSS-related loaders

* Remove unused webpack-node-externals dependency

* Add missing MiniCssExtractPlugin to Boards/Playbooks production builds

webapp/package.json

@@ -24,9 +24,17 @@
     "chalk": "4.1.2",
     "concurrently": "7.6.0",
     "cross-env": "7.0.3",
+    "css-loader": "6.7.3",
     "eslint": "8.37.0",
     "eslint-plugin-formatjs": "4.9.1",
-    "strip-ansi": "6.0.1"
+    "mini-css-extract-plugin": "2.7.5",
+    "sass": "1.62.1",
+    "sass-loader": "13.2.2",
+    "strip-ansi": "6.0.1",
+    "style-loader": "3.3.2",
+    "webpack": "5.81.0",
+    "webpack-cli": "5.0.2",
+    "webpack-dev-server": "4.13.3"
   },
   "workspaces": [
     "channels",