Telephony: IMS changes for VoLTE and VT.

- Additional APIs in CallManager for IMS calls
- Create separate ImsPhone for IMS calls
- Register IMS phone with CallManager,
  after registering the CDMA base phone as default phone
- Use ImsPhone for IMS specific API calls
- CallManager handles both CS & PS calls

- Add hold, switching and conference capabilities for IMS calls

- VT: Add getCallType api to Phone interface

- Add API to check VT call modify capability

- VT: Add addional call types for VT TX and VT RX

- IMS Conference URI update Call Details

- Supplementary Service Notification support for IMS

- Add ECBM support for ImsPhone

- Expose method to get index of connection

- Add getPhoneInCall utility in CallManager

Change-Id: I4590dc6ba19b33ab0cd7ccab5f8bd0cc5cfa8e72