libstagefright: pass codec importance to rm

MediaCodec passes the codec importance associated with
the codec to the ResourceManager if its part of the
configuration parameter passed as MediaFormat.
And also, the codec importance can be changed through
serParameters.

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: I7b6748c2cbcb3a67ce77fc8472487e6206308987