In current pw master the behavior has been changed to not activate
the "On" profile on alsa devices by default, because of the DeviceReserve
D-Bus API implementation in media-session.

This is a hack here to get the previous behavior. In the future
we should have a way to configure profiles, as well as to pick
a sensible default by autodetection.

This class wraps a SPA monitor and creates all
the devices and nodes as they are being discovered