Rebasing #1155 and applying some fixes. Had to comment out the
`mpd_notify_muxer_listener_unittest` because it depends on
`MockMpdNotifier` from `mpd/base` which has not been ported yet. Can
bring this test back once that has been ported.
Related to #1047
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Co-authored-by: Carlos Bentzen <carlos.bentzen@bitmovin.com>
Co-authored-by: Joey Parrish <joeyparrish@google.com>
Cosmin Stejerean