Add new architecture support for iOS, Android with Windows update

[jimmyltsinn]

This changes update add new architecture support and preserved legacy architecture support for iOS and Android, and align implementation with legacy architecture in Windows.

While our team has been recently upgrading an app built with React Native Windows, we notice that we are failed to build under Windows with latest version. We have referenced a few outstanding PRs and aggregate changes from #732 with latest 1.5.9 release, and align the method name across iOS, Android and Windows.

The changes has been verified with a blank app of React Native 0.79.6, bundled in Example folder.

	New Architecture	Legacy Architecture
iOS	✅	✅
Android	✅	✅
Windows	(Not tested)	✅ (`old/uwp-cpp-app`)

While we have tested the app with above scenario, we believe there are still scenario missed in testing. Please feel free to report further issue found in this PR.

The changes in this PR has been also published to npm as a forked scoped package @pasteltech/react-native-config at version 1.6.0-rc.0 for sorely testing purpose. We hope this PR could merge into main branch and release of react-native-config and resolve some issues facing by the community.

[carloswbarros]

I'm trying to test with @pasteltech/react-native-config
but what do I put in the build.gradle?
apply from: project(':react-native-config').projectDir.getPath() + "/dotenv.gradle" doesn't seem to work.
Error:

A problem occurred evaluating project ':app'.
> Project with path ':react-native-config' could not be found in project ':app'.

Edit:
Got it working by putting the whole path: apply from: "../../node_modules/@pasteltech/react-native-config/android/dotenv.gradle"

[Gnative]

A lot of work here, looks good thou I only tested on Android, iOS on 0.79.6 new/old arch - just added this to package.json with the below and npm install to test.

    "react-native-config": "lugg/react-native-config#pull/852/head",

[Arthurmtro]

I've just tested on the react-native-windows preview 0.80.0-preview.8 with the old arch, and I confirm that this was the only solution I had to make it work !

we need this to merge haha