stream-pipewire: Add a helper script for the pipewire backend

This is mostly for a easy way to stream out content from the pipewire
backend.

Similarly to the rdp script this can used on the server after checking the
pipewire id. On the remote side the rdp script can be used. Script
mentions that as usage.

Signed-off-by: Marius Vlad <marius.vlad@collabora.com>