ci: Ensure that eslint runs on all frontend code (no-changelog) (#4602)

* ensure that eslint runs on all frontend code

* remove tslint from `design-system`

* enable prettier and eslint-prettier for `design-system`

* Delete tslint.json

* use a single editorconfig for the repo

* enable prettier for all code in `design-system`

* more linting fixes on design-system

* ignore coverage for git and prettier

* lintfix on editor-ui

packages/design-system/src/css/base.scss

@@ -1,3 +1,3 @@
-@forward "common/var.scss";
-@import "common/transition.scss";
-@import "icon.scss";
+@forward 'common/var.scss';
+@import 'common/transition.scss';
+@import 'icon.scss';