Delete old classes related to Modal's old implementation which was based on Dialogs

[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

This reverts commit a9b9d8379c.

Test Jenkins

* Migrate to react v16.3 lifecycle & Add backward compatibility for older React versions

* remove yarn.lock

* migrate js and java to mergeOptions

* migrate ios to mergeOptions

* Rename to onChildWillAppear

* update roadmap

on clicking the outside of the sideMenu area sideMenu not closing,
because there is a problem in the code which i modified now

Each animation (push, pop etc) can be enabled or disabled separately

I made the text a little more punchy and easy to read.

The following  https://github.com/wix/react-native-navigation/pull/3006 implemented this functionality