Split Webpack configuration into sub-packages

[Anahkiasen]

I don't personally use CRA, but as a resource and project it is probably one of the most fine-tuned packages that you can find on NPM. Whenever I feel the need to look up what the ideal configuration of something is (Babel, Webpack, etc.) I double check how this package does it first.

Now a lot of good has come out of this project, per example the Babel preset is available as a standalone package. It would be very useful if the Webpack configuration used by CRA was also split into a separate project to be consumed by other people.

Maybe using something like webpack-config to easily extend/merge it from third party projects.

[dinukadesilva]

relates to #1308

[gaearon]

One of the problem in making it modular is that it makes it harder for people to tune it after ejecting. They have to learn yet another abstraction which may not satisfy their particular use case. If one such solution gained enough traction in the community and became a de facto standard then maybe. But this hasn't happened yet.

[gaearon]

Probably don't do this for now.