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-sync.svg

@@ -1 +1 @@
-<svg viewBox="0 0 16 16" class="svg octicon-sync" width="16" height="16" aria-hidden="true"><path fill-rule="evenodd" d="M8 2.5a5.487 5.487 0 00-4.131 1.869l1.204 1.204A.25.25 0 014.896 6H1.25A.25.25 0 011 5.75V2.104a.25.25 0 01.427-.177l1.38 1.38A7.001 7.001 0 0114.95 7.16a.75.75 0 11-1.49.178A5.501 5.501 0 008 2.5zM1.705 8.005a.75.75 0 01.834.656 5.501 5.501 0 009.592 2.97l-1.204-1.204a.25.25 0 01.177-.427h3.646a.25.25 0 01.25.25v3.646a.25.25 0 01-.427.177l-1.38-1.38A7.001 7.001 0 011.05 8.84a.75.75 0 01.656-.834z"/></svg>
+<svg viewBox="0 0 16 16" class="svg octicon-sync" width="16" height="16" aria-hidden="true"><path fill-rule="evenodd" d="M8 2.5a5.487 5.487 0 0 0-4.131 1.869l1.204 1.204A.25.25 0 0 1 4.896 6H1.25A.25.25 0 0 1 1 5.75V2.104a.25.25 0 0 1 .427-.177l1.38 1.38A7.001 7.001 0 0 1 14.95 7.16a.75.75 0 1 1-1.49.178A5.501 5.501 0 0 0 8 2.5zM1.705 8.005a.75.75 0 0 1 .834.656 5.501 5.501 0 0 0 9.592 2.97l-1.204-1.204a.25.25 0 0 1 .177-.427h3.646a.25.25 0 0 1 .25.25v3.646a.25.25 0 0 1-.427.177l-1.38-1.38A7.001 7.001 0 0 1 1.05 8.84a.75.75 0 0 1 .656-.834z"/></svg>