Adds ReactNative plugin (#5018)

plugins/react-native/README.md

+# React Native 
+
+**Maintainer:** [BilalBudhani](https://github.com/BilalBudhani)
+
+### List of Aliases
+
+Alias | React Native command
+------|---------------------
+**rnand** | *react-native run-android*
+**rnios** | *react-native run-ios*
+**rnios4s** | *react-native run-ios --simulator "iPhone 4s"*
+**rnios5** | *react-native run-ios --simulator "iPhone 5"*
+**rnios5s** | *react-native run-ios --simulator "iPhone 5s"*
+

plugins/react-native/react-native.plugin.zsh

+alias rnand='react-native run-android'
+alias rnios4s='react-native run-ios --simulator "iPhone 4s"'
+alias rnios5='react-native run-ios --simulator "iPhone 5"'
+alias rnios5s='react-native run-ios --simulator "iPhone 5s"'
+alias rnios='react-native run-ios'
+