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

When updating buttons with mergeOptions, existing custom buttons are unmounted and then recreated. This commit adds an optimisation which prevents the react components from being recreated.
To avoid unnecessary recreation, add an `id` to the component. If an existing react view is found for that id, it will be reused.