Support audio_format=caf for AnkiMobile

[abdnh]

No description provided.

[tatsumoto-ren]

Since Apple's operating systems are malware, wouldn't merging this PR suggest that we affirm the use of non-free software instead of encouraging people to ditch it?

[abdnh]

AnkiMobile is the sole way to support Anki's creator, and it essentially funds the development of the free computer version, even AnkiDroid to some degree. I use free alternatives whenever possible, but I think it's unrealistic for most people to completely ditch non-free software.

[tatsumoto-ren]

Ajatt-Tools is funded solely by donations. It's unfortunate that some people still spend money on proprietary software. Essentially they pay for being mistreated. And it makes the problem worse because it gives developers incentive to continue making proprietary software.

It's totally possible to completely abandon proprietary software. I and many Ajatt-Tools members have done it. And we welcome others to do it too.

[rVnPower]

I don't really know what this PR offers.

[tatsumoto-ren]

Apparently the proprietary Anki app is not capable of playing ogg/opus files. But it can play the caf format. We can add support for the caf format, but there's a possibility that as a result people will be more likely to continue using iThings instead of getting rid of them.