pulse-server: Implement module-pipe-sink

Implements #934 (closed).

Tested using

pactl load-module module-pipe-sink channels=2 rate=44100 format=float32le
pacat /tmp/music.output --channels=2 --rate=44100 --format=float32le

Run a gstreamer pipeline

gst-launch-1.0 -v filesrc location=Jambi.mp3 ! mpegaudioparse ! mpg123audiodec ! audioresample ! audio/x-raw,channels=2,rate=44100 ! pipewiresink

Do the necessary changes in pavucontrol.