Allow adding songs to multiple playlists at once. (#995)

* Add support for multiple playlists

* Fix lint

* Remove console log comment

* Disable 'check' when loading

* Fix lint

* reset playlists on closeAddToPlaylist

* new playlist: accomodate string type on enter

* Fix lint

* multiple new playlists are added correctly

* use makestyle()

* Add tests

* Fix lint

ui/package.json

@@ -33,12 +33,14 @@
     "@testing-library/react-hooks": "^5.1.1",
     "@testing-library/user-event": "^13.1.2",
     "css-mediaquery": "^0.1.2",
-    "prettier": "^2.2.1"
+    "jest-environment-jsdom-sixteen": "^1.0.3",
+    "prettier": "^2.2.1",
+    "ra-test": "^3.14.3"
   },
   "scripts": {
     "start": "react-scripts start",
     "build": "react-scripts build",
-    "test": "react-scripts test",
+    "test": "react-scripts test --env=jest-environment-jsdom-sixteen",
     "lint": "eslint -c node_modules/eslint-config-react-app/index.js src/**/*.js",
     "eject": "react-scripts eject",
     "prettier": "prettier --write src/*.js src/**/*.js",