This module allows wireplumber to create static nodes that match a specific
device using a spa node factory. Matching is optional, and if there is no match,
the node will always be created.

This keeps track of the default endpoint and selects a default
based on endpoint priorities when devices are discovered

This will be replaced by a new policy based on configuration files

This is no longer used and it is the wrong approach anyway.
A mixer GUI needs to list all endpoints and figure out the controls
from the streams on its own, using the new endpoints API.

This is not used by AGL anymore and it will go away *anyway*
when we switch to the configuration-based logic for
creating endpoints

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.

* Every client has a priority based on its role
* For playback, we allow only a single client to play at a time
* For capture, we allow all clients to capture simultaneously
* Every time the "selected" device changes (either because devices
  are discovered/removed or because the user changed the selection),
  the clients are re-linked to the new "selected" device.
* When a playback client quits and there are others waiting unlinked,
  the highest priority one is linked automatically.
* This also properly fixes re-linking the correct client(s) to the
  correct device(s) when wireplumber exits and restarts.

Currently, the stream names have to be duplicated in the configuration
file. This is going to change in a future version.

Currently this will just grant full access to all clients.
A future version will refine that to grant access to specific
objects only.

This provides high level volume controls for the AGL audiomixer
binding and the applications using it.