Add setMediaButtonBroadcastReceiver API

This API will replace the existing
setMediaButtonReceiver(PendingIntent) API to address the issue that
PendingIntent obejcts should not be persisted over reboots.

See go/replace-setmediabuttonreceiver for more details.

Bug: 161334442
Test: atest CtsMediaTestCases:android.media.cts.MediaSessionTest
Change-Id: I4ece6b8595b5f572426b96fbf06edb34c93eeb50