Remove OMX dependency from MediaPlayerService

Also, convert Android.mk files to Android.bp.

Test: make cts -j123 && cts-tradefed run cts \
-m CtsMediaTestCases \
-t android.media.cts.MediaPlayerTest

Bug: 67652488
Change-Id: I7172d1a2513826a5dafbe51245af11d863f50585