Allow the framework to communicate with netd via a binder service

This will allow us to provide a better interface between Java
services (e.g., ConnectivityService) and netd than the current
FrameworkListener / NativeDaemonConnector interface which uses
text strings over a Unix socket.

Bug: 27239233
Change-Id: If40582ae2820e54f1960556b7bf7e88d98c525af