wireplumber: add basic policy support based on role priorities

wireplumber: add basic policy support based on role priorities

* Every client now 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.

George Kiagiadakis (7):
      m-client-permissions: ref-count the client data and re-work code for safety
      policy: take into account the role of the client when linking it
      Merge branch 'doc-fix' into 'master'
      Merge branch 'delay-unhandled-clients' into 'master'
      config: allow nested blocks, in case a property has a dictionary value
      policy: implement a basic policy based on role priorities
      simple-policy: remove the idle callback when the object finalizes

Julian Bouzas (3):
      Fix doc warnings
      audio-client-module: added new module to load clients after softdsp endpoints are created
      simple-policy: delay unhandled enpoints if target is not found

Bug-AGL: SPEC-2473

Change-Id: Ia37f236a8cac8b5f1f0d5e7409c50d4e7cb8a2da
Signed-off-by: George Kiagiadakis <george.kiagiadakis@collabora.com>