Add a simple wrapper for IpClient.

This takes care of boilerplate tasks such as clearing calling
identity, catching RemoteExceptions, and converting to stable
parcelable objects.

Bug: 131206163
Test: builds, boots, wifi works
Test: atest FrameworksNetTests
Change-Id: I7cbe5fc105503d0983cba2bf77fb0097bd20d9ba
Merged-In: I7cbe5fc105503d0983cba2bf77fb0097bd20d9ba
(cherry picked from commit 67a6f782)