refactor(client): move assets folder into app and remove rdash-ui dep (#3883)

* refactor(assets): use rdash css

* chore(build): remove rdash dep

* refactor(client): move assets folder into app

webpack/webpack.common.js

@@ -115,6 +115,7 @@ module.exports = {
       Docker: path.resolve(projectRoot, 'app/docker'),
       Extensions: path.resolve(projectRoot, 'app/extensions'),
       Portainer: path.resolve(projectRoot, 'app/portainer'),
+      '@': path.resolve(projectRoot, 'app'),
     },
   },
 };