Summary:
**History:** This component was originally introduced into React Native core in D52712758, to replace UIManagerModule.showPopupMenu().
**Problem:** But, React Native core should be lean. Adding this component to React Native bloats the core.
**Changes:** So, this diff pulls PopupMenuAndroid out into its own package in the react-native GitHub repository.
In the future, this will be migrated to a community package!
Changelog: [Android][Removed] Move PopupMenu out of React Native core
Reviewed By: NickGerleman
Differential Revision: D53328110
fbshipit-source-id: 469d8dc3e756c06040c72e08fa004aafa1bd6e18
Ramanpreet Nara