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-pencil.svg

@@ -1 +1 @@
-<svg viewBox="0 0 16 16" class="svg octicon-pencil" width="16" height="16" aria-hidden="true"><path fill-rule="evenodd" d="M11.013 1.427a1.75 1.75 0 012.474 0l1.086 1.086a1.75 1.75 0 010 2.474l-8.61 8.61c-.21.21-.47.364-.756.445l-3.251.93a.75.75 0 01-.927-.928l.929-3.25a1.75 1.75 0 01.445-.758l8.61-8.61zm1.414 1.06a.25.25 0 00-.354 0L10.811 3.75l1.439 1.44 1.263-1.263a.25.25 0 000-.354l-1.086-1.086zM11.189 6.25L9.75 4.81l-6.286 6.287a.25.25 0 00-.064.108l-.558 1.953 1.953-.558a.249.249 0 00.108-.064l6.286-6.286z"/></svg>
+<svg viewBox="0 0 16 16" class="svg octicon-pencil" width="16" height="16" aria-hidden="true"><path fill-rule="evenodd" d="M11.013 1.427a1.75 1.75 0 0 1 2.474 0l1.086 1.086a1.75 1.75 0 0 1 0 2.474l-8.61 8.61c-.21.21-.47.364-.756.445l-3.251.93a.75.75 0 0 1-.927-.928l.929-3.25a1.75 1.75 0 0 1 .445-.758l8.61-8.61zm1.414 1.06a.25.25 0 0 0-.354 0L10.811 3.75l1.439 1.44 1.263-1.263a.25.25 0 0 0 0-.354l-1.086-1.086zM11.189 6.25 9.75 4.81l-6.286 6.287a.25.25 0 0 0-.064.108l-.558 1.953 1.953-.558a.249.249 0 0 0 .108-.064l6.286-6.286z"/></svg>