Add README for setTrackerId, and update recommended installation procedure
Add README for setTrackerId, and update recommended installation procedure

mmiani/react-native-google-analytics-bridge,idehub/react-native-google-analytics-bridge,idehub/react-native-google-analytics-bridge,mmiani/react-native-google-analytics-bridge,rdesai40/react-native-google-analytics-bridge,rdesai40/react-native-google-analytics-bridge,mmiani/react-native-google-analytics-bridge,rdesai40/react-native-google-analytics-bridge,rdesai40/react-native-google-analytics-bridge,idehub/react-native-google-analytics-bridge,idehub/react-native-google-analytics-bridge,mmiani/react-native-google-analytics-bridge