Add Pipewire aout module

This MR add the pipewire aout module, developed by @Courmisch

Note:

The commit "pulse: fail if the server is Pipewire" was copied manually from gitlab: !4751 (closed). I modified it to initialize sys->is_pipewire before calling pa_context_get_server_info, if that is OK with you Rémi.

Issues/TODO:

• Lipsync is wrong, the audio is 60-80ms late, it also happens when using time_get
• 1-3 video frames are dropped when using this module, it does not happen when using time_get
• Test passthrough