Telephony: IMS changes for VoLTE and VT.

- Additional APIs in CallManager for IMS calls

- 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: Iefbe7a8c1ea1f3f45d9fbbd555fe184b170eb242
(cherry picked from commit ff1c808da67f4aa213ef0b0942763830a4eea83a)
(cherry picked from commit ba31037789535ef8ddffe87fcce1f29ded694048)