This is the second phase of updating sonar's dependencies. Many of these ones are focused more on the frontend side of things, including updating to newer versions of react. This also switches us over to using the "module" type in `package.json`. This tells node that we're operating using ES6 modules rather than CommonJS imports. This eliminates the need to use babel-node, which simplifies things considerably and should improve performance a lot. The one casualty of this is the newrelic integration, which would need external configuration (since apparently the `newrelic.js` file can't be loaded in ESM mode). I don't really care about newrelic monitoring here, so this is fine for now. I've also deleted the old `load-old-data.js` script. This was used when we moved the data storage over from MongoDB to SQL, but isn't necessary anymore. Testing Done: Logged in and checked various features. In particular, tested parts of the UI affected by the selectize update (things like group membership selectors), and React-MDE (the status report markdown editor).