Created by: ianschmitz
This PR brings back support for configuring the build output based on browserslist, as well as supporting @babel/polyfill in the entrypoint. This provides a huge improvement to the dev experience as it allows targeting modern browsers in development which makes certain language features like async/await much nicer to debug, while still supporting a broad range of browsers in production.
Including ie 9 in browserslist:
Modern browsers:
Closes #6198 (closed).