resourcemanager: define resource model

This change:
- defines a resource model interface
- defines a base resource model that implements the current (default) resource model
- integrates the resource model with the resource manager service
This change allows extending or replacing the resource models in the future.

Bug: 294886363
Test: atest android.media.misc.cts.ResourceManagerTest
      atest android.media.misc.cts.ResourceManagerMultiTest
      /data/nativetest64/ResourceManagerService_test/ResourceManagerService_test
      /data/nativetest64/ResourceObserverService_test/ResourceObserverService_test
Change-Id: Ifbdd3de90bf9fc5e21f2e1eaa9993dcc0983810a