closes #3387

There was an issue where ReactRootView was not unmounted if it was destroyed when it was hidden.

This change is introduced so BottomTabs are actually rendered when created
This commit also fixes back button issue where it wasn't properly added when pushing screens.

BottomTabs are all mounted when created, selecting a tab only changes visibility

* 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 should fix conversion issues found in RN 0.54

* Migrate to jest to support parallel ios simulator from detox

* When e2e lint only ts or js files

* Remove mocha from deps and decrease from 480000ms to 180000ms

* Support RN 0.55.4

This commit adds support for RN 0.55.4 by introducing version specific build flavors - reactNative51

* Update scripts after introducing build flavors

* Update Android installation instruction on specifying build flavor

* add option to disable tabbar icon tints and add custom selected icons

*  update docs for disabling tabbar icon tint and selectedIcon

* move new options to ios-specific section in docs

* delete trailing comma in docs

* Screen background option fixed in iOS

* fix unit tests

* add addicional options to tabbar

* fix tests

* [ios11+] Add searchBar option for topBar

* Fix formatting and linter issues

* Add docs about topBar.searchBar

* Fix missing semicolons

* Revert prettier changes

* Add js tests for onSearchBarUpdated to achieve 100% coverage

* Mark searchBar test as :ios: specific