Add documentation to integrate Wix's RNN v2

[andresesfm]

Currently no information on how tin integrate Wix's React-Native-Navigation V2. There are different Steps than on V1 which is already included in the documentation.

These are my proposed changes to docs/setup-android.md :
#1239

[itoys]

Hi @andresesfm,
Thanks for suggestion, I'll take a look on your PR a bit later!

[andresesfm]

I have fixed the review comment, please take a look

[itoys]

@andresesfm
Merged, thanks!

[eduardopelitti]

Sorry to bump this old thread, but I think it'd be nice to add this code snippet to the Docs:

wix/react-native-navigation#3040 (comment)

Otherwise, you get packager errors when running the application on Android due to a missing index.android file.

I could send a PR for it, if you think it's Ok @itoys.