Update JS dependencies (#15033)

* Update JS dependencies

- Update all JS dependencies
- For octicons, rename trashcan to trash
- For svgo, migrate to v2 api, output seems to have slightly changed but icons look the same
- For stylelint, update config, fix custom property duplicates
- For monaco, drop legacy Edge support
- For eslint, enable new rules, fix new issues
- For less-loader, remove deprecated import syntax

* update svgo usage in generate-images and rebuild logo.svg with it

public/img/svg/octicon-ruby.svg

@@ -1 +1 @@
-<svg viewBox="0 0 16 16" class="svg octicon-ruby" width="16" height="16" aria-hidden="true"><path fill-rule="evenodd" d="M3.637 2.291A.75.75 0 014.23 2h7.54a.75.75 0 01.593.291l3.48 4.5a.75.75 0 01-.072.999l-7.25 7a.75.75 0 01-1.042 0l-7.25-7a.75.75 0 01-.072-.999l3.48-4.5zM4.598 3.5L1.754 7.177 8 13.207l6.246-6.03L11.402 3.5H4.598z"/></svg>
+<svg viewBox="0 0 16 16" class="svg octicon-ruby" width="16" height="16" aria-hidden="true"><path fill-rule="evenodd" d="M3.637 2.291A.75.75 0 0 1 4.23 2h7.54a.75.75 0 0 1 .593.291l3.48 4.5a.75.75 0 0 1-.072.999l-7.25 7a.75.75 0 0 1-1.042 0l-7.25-7a.75.75 0 0 1-.072-.999l3.48-4.5zM4.598 3.5 1.754 7.177 8 13.207l6.246-6.03L11.402 3.5H4.598z"/></svg>