Investigate reusing `AudioSink`

[BD103]

I don't know how keen to actually go forward with it I am, but I'll mention that rodio 0.18 includes the change I made to SpatialSink, which theoretically allows the current audio system to be restructured to reuse its audio sinks.

Originally posted by @mweatherley in #13612 (comment)

rodio's SpatialSink can now be cleared after RustAudio/rodio#548 was merged, which means now both Sink and SpacialSink support being re-used. It may be worth investigating whether this is worth implementing, or if we should just skip this and go straight to the kira migration.