Introduce ControllerCallbackLink

In order to avoid direct AIDL usages in framework, this CL introduces a
new class ControllerCallbackLink which can prevent usages of
ISessionControllerCallback.

Bug: 122169124
Test: make update-api -j / make -j
      atest CtsMediaTestCases:android.media.cts.MediaSessionTest
      atest CtsMediaTestCases:android.media.cts.MediaControllerTest
Change-Id: I860ea56afc046dd91e065ef207d374c0aa490c8f