Will be used for shared element transition showcase

* Fix topBar transparent background on iOS 12

* Fix unit test iOS destination

Called each time a screen is popped, either due to `Navigation.pop` or pop gesture.
closes #3941 

Navigation.events().registerScreenPoppedListener(({ componentId }) => {

});

Default options were not taken into account when determining bottom inset.
Closes #5738

bottomTab.icon accepts a string as well as required asset - this was not reflected properly in TypeScript and implementation was missing from Android.
closes #5759

Fix modal dismissed with swipe gesture emits wrong componentId

* Remove main window backgroundColor
* Better interface for TopBarPresenter

Fab has been broken since v3. This is a very temporary fix until we refactor it and upgrade to fab from AndroidX

Improved attach mode together unit test

Add iOS support for `bottomTabs.attachMode`.
This property controls when BottomTabs children are attached to hierarchy and when their React views are created.

By default, RNN attaches all children at the same time which might impact loading time as a few screens are instantiated at once.
Using `afterInitialTab` or `onSwitchToTab` generally leads to improved start up time.

Since migrating to CocoaPods, we had to pod install to compile local changes - using legacy build system works around that.

Import lodash sub modules

* Fix dismissed modal event by swiping down gesture

* Fix typescript

modalsDismissed was missing from event declaration. This obscure property represents the number of modals which were dismissed. When dismissModal is called it's 1 and when dismissAllModals is called, it's the number of modals which were visible on screen.

Hey, it is me again 🙂So I am just updating the docs due to some changes to my [starter](https://github.com/kanzitelli/react-native-navigation-starter) which are upgrading RNN to v4 and adding implementation of app logic using [MobX State Tree](https://github.com/mobxjs/mobx-state-tree) as an alternative to Redux.

Related to #4861

* Fix black topBar background color

* Fix largeTitle behavior on iOS 13

* Set  as default modalPresentationStyle

* Sets the system default modalPresentationStyle

* Fix tests

* Fix unit tests

* Fix unit tests

* Add modal.swipeToDismiss option

* Closes #5622

* Fix unit tests

Under certain configurations, creating ReactNativeHost before SoLoader.init throws an exception.
This commit changes the behaviour of the main ReactGateway constructor to ensures host is created after SoLoader.init.