* Refactored backButton api

* Move StackController to separate package

Implement BackButtonOptions

* Somewhat simplify StackController creation in tests

* Pull backButton logic from StackController

* Handle all TopBar button options in TopBarButtons

* fix back button on iOS

This commit add support for changing the TopBar height as well as changing
the height of custom component used as background

Fixes #3138.

[Breaking[ Modal refactor

* [Breaking] Showing modal removes the previously visible ViewController from hierarchy
* Modal implementation does not rely on Dialog
* Modal view is added to `content` layout
* Overlay is added to `root` layout, on top of the application's content
* Introduce StackControllerBuilder
* Show modal with animation
* Dismiss modal with animation
* Add previous modal at index 0
* Add root at index 0
* dismissAllModals dismisses only top modal with animation

* pass props for topBar background component

* refactored custom components

* pass props for topBar background component

* refactored custom components

* refactored RNNOptions object

* Use margin to control component position relative to TopBar

RelativeLayout rules caused excessive CPU usage due to issues with RN's
keyboard detection mechanism (based on global layout listener)

* Skip custom transition e2e on Android

* Improved the clarity of the top-level API doc (#2984)

I clarified some of the language here so that it is easier for the beginner to understand. (It was a little bit awkward before)

* Increase gradle daemon process memory

* Disable Orientation test on Android

* Fix SideMenu e2e

* Fix popTo

* Use margin instead of RelativeLayout rules to align component to BottomTabs

Rules caused excessive CPU usage due to RN issue with global layout listener
and keyboard visibility detection.

* Update README.md

for triggering build

* Update README.md

* Consolidate pop and animatePop

* Update top-level-api.md ... more copyediting. (#3002)

Further clarification of some of the top level API stuff.

* popTo animates top screen

* Refactor component options on Android

* Stop processing passProps from options

* removed comments

Manage the view with controller which handles lifecycle

Previously, all options were cleared and reapplied whenever mergeOptions was called

* Clear text when component is used in title
* Measure title component to first child's width

* Refactor TopBar options, introduce title options

* Update background to new api

* Refactored topBar options on iOS

* Initial react component in TitleBar android

* set height to react view in TitleBar

* fix tests and lint

* ios unit tests fix

* TopBar custom buttons initial commit

* f

* Consolidate TopBarButtonController and TopBarButton

* Move Toolbar related stuff to TitleBar

* TitleBarTest

* More tests