React stack pack

We have an initial [set](https://github.com/GoogleChrome/lighthouse-stack-packs/blob/master/packs/react.json) of React-specific suggestions! However, we would love to have more members from the community review and add more if possible.

1. Do the already populated performance audit suggestions look good? Should they be changed in any way?
2. For all the remaining performance audits (currently [blank](https://github.com/GoogleChrome/lighthouse-stack-packs/blob/master/packs/react.json)), can we add a React-specific suggestion that would be relevant to developers?

All thoughts, comments and PRs appreciated!