Add new provisioning flag for VOIMS opt-in

Bug: 177009570
Test: By Manual
1. Call setProvisioningIntValue() and getProvisioningIntValue()

2. Enable/disable the value and dial a VoLTE call
2-1. Set value to 1
2-2. Dial a call
2-3. From ImsPhoneCallTracker and GsmCdmaPhone's log, VoLTE is
 registered and device is trying IMS PS call
2-4. Set value to 0
2-5. Dial a call
2-6. From ImsPhoneCallTracker and GsmCdmaPhone's log, VoLTE is
unregistered and device is trying (non-IMS) CS call

3. atest

Change-Id: I0b8af8fe6c9a34a56f9e2275df0a03ba093f439e
Merged-In: I0b8af8fe6c9a34a56f9e2275df0a03ba093f439e