Summary:
1. Fix bug: Android project do not delete font files when run `react-native unlink`.
2. Add feature, link images to iOS project when run `react-native link`.
Closes https://github.com/facebook/react-native/pull/14801
Differential Revision: D5890051
Pulled By: hramos
fbshipit-source-id: 28223d181ac5ed51d70df29a56eb56b2cce9aecb