Leverage React's makePageRoutes to generate page routes

Investigate how much code we can get rid of in our [routes-utls](https://github.com/elvingm/jewish-currents-static/blob/staging/routes-util.js) by leveraging [React's `makePageRoutes`](https://github.com/nozzle/react-static/blob/master/docs/node-api.md#makePageRoutes).