Base Implementation of SipTransport

Implements create/destroy procedures for app/ImsService. This is the
first in a series of CLs to implement SipTransport in telephony.

- SipTransportController: manages the SipDelegate connections between IMS app and
ImsService for a single slot. SipDelegates are created and destroyed for the
subId associated with the slot.

- SipDelegateController: SipTransportController creates a new SipDelegateController
for each request from an IMS application. The SipDelegateController maintains
the SipDelegate created for the feature tags assigned to it from SipTransportController.

- SipDelegateBinderConnection: Connection to SipDelegate on ImsService side. Can be
brought up/down as the associated features change.

- DelegateStateTracker/MessageTransportStateTracker: wrapper around binder to IMS
application's implementation of SipDelegateConnection callbacks.

Test: atest TeleServiceTests
Change-Id: Ieabd13aa4c54fa069ef5fa1298b1749e4192e583
17 files changed