Document CryptoInfo Settings for CENC 2016 & HLS Audio

Adds additional documentation that clarifies how to set up CryptoInfo
objects for CENC 2016 decryption schemes, in particular for the case of
HLS SAMPLE-AES Audio.

Bug: 62503021
Test: make docs
Change-Id: Ia21ef62a4144e7b41b0216ba0b968ff6c52d0297
1 file changed