Source of AV1/Config

- aomedia/aom/common/av1_config.c
-- https://aomedia.googlesource.com/aom/+/refs/heads/master/common/av1_config.c#386
- aomedia/aom/test/av1_config_test.cc
--  https://aomedia.googlesource.com/aom/+/refs/heads/master/test/av1_config_test.cc

- AV1CodecConfigurationBox  Box('av1C')
--  https://aomediacodec.github.io/av1-isobmff/#av1codecconfigurationbox-syntax