[v2] Show LightBox Equivalent

[RomualdPercereau]

Issue Description

There is actually no equivalent of showLightBox in v2
The new version introduce 2 features : showModal and showOverlay.

ShowModal

This is supposed to push a new full screen controller, which works like Navigation.push

ShowOverlay

There is no animation, no background management, interceptTouchOutside doesn't work as expected (#4622)

You can bullshit to have something like the previous showLightBox : #4060.

Alternatives

The cleaner way to display a modal on v2 is probably the official way: https://facebook.github.io/react-native/docs/modal

Any Plans ?

Any plans to replace this feature with should be on the native side and done by the navigator?

Environment

• React Native Navigation version: 2.7.1
• React Native version: 0.57
• Platform(s) (iOS, Android, or both?): Both
• Device info (Simulator/Device? OS version? Debug/Release?): Alls

[guyca]

Bullshitting as shown in #4060 seems like a great idea!
lightbox isn't implemented in v2 because it's not a native component and can be easily implemented (bullshit as you describe it) using Overlay.
Want to handle touch events outside of the actual lightbox? use TouchableWithoutFeedback, don't want to repeat yourself? open source your bullshit.

good luck and happy bullshitting.