Stop limiting quantum/buffer to 8192

This may be plenty for 48khz-only audio but anything beyond that is bottlenecked by this limit. I think this should be at least 96*192=18432, ideally - 96*768=73728. All non-realtime players have large, 100-200ms, buffers and they introduce unnecessary strain when forced to "low" quantum, especially if there is intermediate CPU-heavy post-processing.

This especially noticeable on unreleased openal version with native PW backend which may be used in a lot of emulators and players like mpv and strawberry/clementine.