Update JS dependencies and webpack (#14118)

* Update JS dependencies

- Update all JS dependencies
- Adapt webpack config for version 5
- Update to Less 4.0, adapting usage of removed mixin syntax
- Enable new ESLint rules and fix discovered issues

* update license-webpack-plugin to fix missing licenses

* update license-webpack-plugin once more to get webpack into the license output

* switch to license-checker-webpack-plugin again for performance

* update deps again

Co-authored-by: Lauris BH <lauris@nix.lv>

.eslintrc

@@ -346,6 +346,7 @@ rules:
   unicorn/catch-error-name: [0]
   unicorn/consistent-function-scoping: [2]
   unicorn/custom-error-definition: [0]
+  unicorn/empty-brace-spaces: [2]
   unicorn/error-message: [0]
   unicorn/escape-case: [0]
   unicorn/expiring-todo-comments: [0]
@@ -361,6 +362,7 @@ rules:
   unicorn/no-for-loop: [0]
   unicorn/no-hex-escape: [0]
   unicorn/no-keyword-prefix: [0]
+  unicorn/no-lonely-if: [2]
   unicorn/no-nested-ternary: [0]
   unicorn/no-new-buffer: [0]
   unicorn/no-null: [0]
@@ -377,6 +379,7 @@ rules:
   unicorn/prefer-add-event-listener: [2]
   unicorn/prefer-array-find: [2]
   unicorn/prefer-dataset: [2]
+  unicorn/prefer-date-now: [2]
   unicorn/prefer-event-key: [2]
   unicorn/prefer-includes: [2]
   unicorn/prefer-math-trunc: [2]