Pipewire sink and source

[gavv]

Last revised: Oct 2023

Not to be confused with pipewire modules for roc (#459).

Currently, when roc command-line tools (roc-recv, roc-send) run on pipwire, they use pulseaudio compatibility/emulation layer of pipewire. We probably want to implement native pipewire writer (in roc source code it's called sink) and reader (in roc source code it's called source) using pipewire APIs, to avoid unnecessary layers. See https://github.com/roc-streaming/roc-toolkit/issues/446#issuecomment-872932278

API: https://docs.pipewire.org/group__pw__stream.html

See also similar task #231.