telephony: IMS changes for VoLTE and VT

- Add IMS phone type constant
- Add system property persist.radio.calls.on.ims.
  It is set to true if VoLTE/VT calls are supported,
  false otherwise.

Change-Id: I9b2ea0e58bd75598c519ff710a93d7667a9c7993
Telephony: Add enable/disable APIs for Cdma CMAS

Add enable/disable APIs for Cdma broadcast to ISms.aidl

Change-Id: I8fb563d92691d0ce97395ed283165dc9179b586a