Feature/add example ios app

[tkow]

For #200.

I want to investigate that problem so, I made minimum application example at RN 0.60.0.
Though this setting only ios app, If owner can accept this cheke it.

How to Check

# project root
yarn install 
# example/ios
pod install
# project root
yarn start

And in Xcode, change provisioning file with setting your team. Then, run button with example scheme.

[tkow]

Close this for integration to #225.