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-diff-added.svg

@@ -1 +1 @@
-<svg viewBox="0 0 16 16" class="svg octicon-diff-added" width="16" height="16" aria-hidden="true"><path fill-rule="evenodd" d="M13.25 2.5H2.75a.25.25 0 00-.25.25v10.5c0 .138.112.25.25.25h10.5a.25.25 0 00.25-.25V2.75a.25.25 0 00-.25-.25zM2.75 1h10.5c.966 0 1.75.784 1.75 1.75v10.5A1.75 1.75 0 0113.25 15H2.75A1.75 1.75 0 011 13.25V2.75C1 1.784 1.784 1 2.75 1zM8 4a.75.75 0 01.75.75v2.5h2.5a.75.75 0 010 1.5h-2.5v2.5a.75.75 0 01-1.5 0v-2.5h-2.5a.75.75 0 010-1.5h2.5v-2.5A.75.75 0 018 4z"/></svg>
+<svg viewBox="0 0 16 16" class="svg octicon-diff-added" width="16" height="16" aria-hidden="true"><path fill-rule="evenodd" d="M13.25 2.5H2.75a.25.25 0 0 0-.25.25v10.5c0 .138.112.25.25.25h10.5a.25.25 0 0 0 .25-.25V2.75a.25.25 0 0 0-.25-.25zM2.75 1h10.5c.966 0 1.75.784 1.75 1.75v10.5A1.75 1.75 0 0 1 13.25 15H2.75A1.75 1.75 0 0 1 1 13.25V2.75C1 1.784 1.784 1 2.75 1zM8 4a.75.75 0 0 1 .75.75v2.5h2.5a.75.75 0 0 1 0 1.5h-2.5v2.5a.75.75 0 0 1-1.5 0v-2.5h-2.5a.75.75 0 0 1 0-1.5h2.5v-2.5A.75.75 0 0 1 8 4z"/></svg>