* Changes to allow active development of UI using webpack and hotloading.
* Update to webpack 4 (will make this work)
* Update webpack.config.js accordingly
* Move webpack.config.js to its own directory
* Split webpack.config.js into base.config.js, dev.config.js and prod.config.js
* Update configs to be "right" for development vs production using --mode
* Want configuration through (optional) local file that is not
checked in
* Updated package.json for newer babel-loader
* Put in a proxy to localhost port 8080 for evelopment server.
This allows "yarn start" to work on the machine where MoonFire's
server is running. This would be the default situation. Users in
a different setup can change the proxy settings.
