IAMF support

[Luiz-Monad]

Hello,

I needed IAMF support to decode fMP4 for my streaming service that I am developing, so I implemented missing boxes and the parser for the IAMF structs based on ffmpeg (so I can dump the debug info from the headers).

Hope its useful, enjoy. (yeah, I know, making pull requests without talking to people before, but it was straight forward adding what was missing and it is a work in progress, any suggestions are welcome)
#480

[tobbee]

Hi @Luiz-Monad, Interesting stuff that I didn't know about. Can you fix the complaints from the build system and rebase and force-push an update? The test coverage was very low, but I think it will improve now when I have changed the coverage settings to look cross packages.