Support for IAMF boxes and dumping headers

[Luiz-Monad]

I used the Opus as reference to implement IAMF.

. implemented the missing IACB and IAMF boxes
. implemented the parser for the IAMF headers based on FFMPEG
. implemented the dumper for IAMF structures so we can debug
. test with a real file from the AOMedia foundation samples

[tobbee]

@Luiz-Monad The change in test coverage parameters and a rebase did not help.
There is way too low to be possible to merge into this repo.

Analysis:

The iamf package (parser and types) is the biggest coverage gap in this PR.
The mp4/iacb_test.go and mp4/iamf_test.go files test the box-level
integration but the IAMF header parsing logic itself has zero coverage.