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-briefcase.svg

@@ -1 +1 @@
-<svg viewBox="0 0 16 16" class="svg octicon-briefcase" width="16" height="16" aria-hidden="true"><path fill-rule="evenodd" d="M6.75 0A1.75 1.75 0 005 1.75V3H1.75A1.75 1.75 0 000 4.75v8.5C0 14.216.784 15 1.75 15h12.5A1.75 1.75 0 0016 13.25v-8.5A1.75 1.75 0 0014.25 3H11V1.75A1.75 1.75 0 009.25 0h-2.5zM9.5 3V1.75a.25.25 0 00-.25-.25h-2.5a.25.25 0 00-.25.25V3h3zM5 4.5H1.75a.25.25 0 00-.25.25V6a2 2 0 002 2h9a2 2 0 002-2V4.75a.25.25 0 00-.25-.25H5zm-1.5 5a3.484 3.484 0 01-2-.627v4.377c0 .138.112.25.25.25h12.5a.25.25 0 00.25-.25V8.873a3.484 3.484 0 01-2 .627h-9z"/></svg>
+<svg viewBox="0 0 16 16" class="svg octicon-briefcase" width="16" height="16" aria-hidden="true"><path fill-rule="evenodd" d="M6.75 0A1.75 1.75 0 0 0 5 1.75V3H1.75A1.75 1.75 0 0 0 0 4.75v8.5C0 14.216.784 15 1.75 15h12.5A1.75 1.75 0 0 0 16 13.25v-8.5A1.75 1.75 0 0 0 14.25 3H11V1.75A1.75 1.75 0 0 0 9.25 0h-2.5zM9.5 3V1.75a.25.25 0 0 0-.25-.25h-2.5a.25.25 0 0 0-.25.25V3h3zM5 4.5H1.75a.25.25 0 0 0-.25.25V6a2 2 0 0 0 2 2h9a2 2 0 0 0 2-2V4.75a.25.25 0 0 0-.25-.25H5zm-1.5 5a3.484 3.484 0 0 1-2-.627v4.377c0 .138.112.25.25.25h12.5a.25.25 0 0 0 .25-.25V8.873a3.484 3.484 0 0 1-2 .627h-9z"/></svg>