v2.0.0

The new version of create-react-app has built-in support to typescript and sass, so we don't need to maintain our own fork of CRA with webpack script changes anymore. This allows us to more closely track to the upstream packages and get fixes automatically (this work was prompted because webpack-dev-server@2 has a high-severity vulnerability which is not fixed till its v3. However, its v3 depends on webpack@4, which breaks a lot of our existing webpack scripts.