React and Vue presets

[knowler]

The addition of webpack.config.preset.js (roots/sage#2083 and roots/sage#2084) opens up a lot of opportunity for adding JS presets such as React and Vue since we have an easier way to override the base Webpack configuration. I know the current plan is to move to Laravel Mix, but for the interim, we could very easily provide these through the installer. These presets would need to be separate from the CSS presets since users would most likely mix and match them.

Thoughts?