Use Core Audio Taps for recording

Subtitle: Trade a big orange dot for a small purple one

This release requires macOS 14.2 "Sonoma"

Instead of requiring an audio device that mirrors the audio data it
receives back to its input (looking like a microphone), we now use a
Core Audio tap on a private aggregate device to listen in on the output
it receives.

That lets us work with just "system audio recording" permissions. These
can be found in:
System Settings -> Privacy & Security -> Screen & System Audio Recording

Microphone access is no longer needed unless the output device that
is tapped also has inputs.

SoundPusherAudio has lost its ability loopback the audio that it receives
to its input, since it no longer provide any input streams.