Use more upstream projects

[arendjr]

As someone who has recently ejected, I noticed you're left with a dependency upon react-dev-utils. That's not a huge issue, but when looking into why it is being used, I noticed there are quite a few cases where react-dev-utils is using custom solutions, even though more "standard" NPM packages exist that do more or less the same thing.

For instance, there's a custom hot reloader plugin, even though Webpack comes with its own. There's openBrowser, which duplicates functionality found in the open package. InlineChunkHtmlPlugin does the same thing as the html-webpack-inline-runtime-plugin package. Maybe at the time the functionality was created, those packages didn't exist... there might have been good reasons. But looking at it today, it's hard to see what the reasons were, and it seems it would benefit both the project's focus as well as users who eject to use more "upstream" packages.

I'm happy to collaborate and create some patches to swap out some of this functionality with existing packages. But is this something the maintainers would welcome? Are there reasons I'm not aware of why those custom implementations are used?