chore: add unimported command, delete some unused files (#410)

Author: artemmufazalov

package.json

@@ -48,6 +48,7 @@
     "//build:embedded": "echo 'PUBLIC_URL is a setting for create-react-app. Embedded version is built and hosted as is on ydb servers, with no way of knowing the final URL pattern. PUBLIC_URL=. keeps paths to all static relative, allowing servers to handle them as needed'",
     "build:embedded": "rm -rf build && PUBLIC_URL=. REACT_APP_BACKEND=http://localhost:8765 npm run build",
     "lint:styles": "stylelint 'src/**/*.scss'",
+    "unimported": "npx unimported --no-cache",
     "package": "rm -rf dist && copyfiles -u 1 'src/**/*' dist",
     "test": "react-app-rewired test",
     "eject": "react-scripts eject",