fix: iOS module

fix: Android: ensure that intent action is not null

fix: iOS add handler to hold/unhold call

Added ability to pass caller name to CallKit in push notification, fi…

…xed incoming caller type

iOS: Adds ability to handle DTMF codes in Callkit

fix: always disable proximityMonitor on iOS when the call is disconne…

…cted

Android: increase minSdkVersion:23, compileSdkVersion:30, targetSdkVe…

…rsion:29

iOS: Twilio Voice SDK v5.2.0, Android: Twilio Voice SDK v4.5.0

iOS: Upgrade TwilioVoice pod to version 2.1

Switch from rnpm to react-native.config.js