Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/49601
Changelog: [internal]
This creates a new module in React Native to define some of the types related to `HostInstance` that are currently defined in `ReactNativeTypes` (synced from the React repo).
We want to remove the types from `ReactNativeTypes` so this is a necessary initial step.
Reviewed By: huntie
Differential Revision: D69996010
fbshipit-source-id: 21cfed4c222e22332936e56aca895fe578809792