resourcemanager: use std::vector for ResourceList

Encapsulate Resource List as vector of resources instead of map.
Since the number of resource is very limited, maintaining it as
std::vector helps with both performance and memory requiremnts.

Bug: 289097671
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: Iec2ead5be1619c7db6d6c978f7398459ce59613b