Read configuration from package.json instead of config.xml

[HarelM]

As of corodva 9.0 it seems that the configuration should be kept and read from package.json and not from config.xml.
Currently it seems that the plugin ignores package.json.
As an initial step support for both config.xml and package.json might be required.

[NiklasMerz]

Could you please provide info about this change with Cordova 9? I did not read about that, yet.

The build scripts are pretty complex and easy to break. I don't have the time to do this change. If you want to give it a try, I would happily review a PR.

[HarelM]

https://cordova.apache.org/announcements/2019/03/18/cordova-lib-release-9.0.0.html
This in particular:
apache/cordova-lib#750
My config.xml file is almost empty expect plugins that have yet to migrate.
I'll read if there's a utility method cordova provides for this...

[HarelM]

@BenjaminPoncet does your PR covers this? Can this issue be closed?