Merge v5 into master

Highlights of this release
* Easier installation
* autolink and reac-native link support
* Shared Element Transition - reimplemented from scratch and new API
* [iOS] showModal animation api parity
* [Android] Animation values are now declared in dp
* [iOS] deprecate topBar.drawBehind
* [Android] RNN is migrating to Kotlin

closes #5904

* Remove OCMock files from being compiled into pod

* Add prepare script to build source when repo is cloned

* Revert package.json change