Config file support

[ampersarnie]

To help with provide additional flexibility for projects and configurations, a configuration file setup should be created.

Identified Areas

• Directory listing - default: array['client-mu-plugins', 'plugins', 'themes']
• Hashed production file names - default: boolean true

[balw]

@ampersarnie Would it be possible to add the configuration for webpack externals to this issue?

With the current config I can not load react in a custom menu page where the block editor is not loaded, I get react undefined.

I've edited the package locally and commented out 'react' and 'react-dom' from the externals and it now loads react.

[ampersarnie]

This has pretty much been addressed with the addition of Custom Webpack Config support. Unless we find additional usecases, I think this can be closed.