Define FEATURE_TELEPHONY_IMS_SINGLE_REGISTRATION feature

Define a new feature that determines if a device supports IMS
single registration and integrate this feature tag into the
SIP transport and provisioning APIs.

Bug: 149426399
Bug: 173715911
Test: atest CtsTelephonyTestCases FrameworksTelephonyTests
Change-Id: Id9ac6a3a69be2072cf28136e98408118b7d9f07f