Add support for Community's Async Storage

[krizzu]

Hello 👋

As part of Lean Core effort in React Native, some modules are extracted into external repos, under RN Community's org.

One of them is Async Storage, used in most of the apps. In order to deprecate old AS module, we've ditched NativeModule's name from AsyncLocalStorage to PlatformLocalStorage.

Currently, RN-windows uses deprecated name, so it'd be great to keep it in sync.

Let me know what you think.

thanks.

[chrisglein]

Customer is currently unblocked. We have limited time for M4 (~1 month) so this will wait for the new year.