interfaces: improve remote API

Add return values to events and method callbacks. This makes it
possible to pass any error or async return value.
Add sync/done/error in both directions so that both proxy and resource
and perform/reply sync and produce errors.
Return a SPA_ASYNC from remote method calls (and events), keep the
sequence number in the connection.
With the core sync/done we can remove the client-node done method and
it's internal sequence number along with the seq number in method calls.
We can also use the method/event async return value to perform a sync
with as the unique sequence number for this method.
Add sync method and done/error event to proxy and resource.

pipewire-pulseaudio

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-Subproject commit 5f9200d9ee58271e60ff24e91e07fa340d71d494
+Subproject commit 61edd78bf4a3bba5edab0ba0c10a7d7f12ff3f7a