ADM (Audio Definition Model) and Dolby Metadata in WAV/RIFF

[JohnnyMarnell]

<chna> and <axml> chunks of Audio Definition Model:

• https://adm.ebu.io/background/what_is_the_adm.html
• https://tech.ebu.ch/publications/tech3285s7
• https://tech.ebu.ch/publications/tech3285s5

Dolby Metadata <dbmd> chunk, e.g. Atmos, AC3, Dolby Digital [Plus]:

• https://tech.ebu.ch/files/live/sites/tech/files/shared/tech/tech3285s6.pdf
• https://github.com/DolbyLaboratories/dbmd-atmos-parser

Notes:

• Had to modify the riff decode fn handlers to receive the chunk size, some need it
• Might be missing some fq + Go idiomatics, happy to correct!