session-manager: split policy and monitor

Separate the session manager in a monitor and policy part.

The monitor manages the devices and endpoints.

The policy watches the nodes/ports/clients and applies the policy
of linking them.

Because both now have a separate connection, we can remove some
hacks in the protocol. When a remote was both the implementer and
user of an object we could get in a deadlock when the user was
blocked waiting and the implementator was blocked sending a reply.
We used to un-busy a client when it was expecting a reply from a
ping or sync for this reason.

Add and use some more keys for the endpoints and streams.

src/modules/module-session-manager/client-endpoint.c

@@ -85,6 +85,8 @@ static int client_endpoint_stream_update(void *object,
 			PW_KEY_ENDPOINT_ID,
 			PW_KEY_MEDIA_CLASS,
 			PW_KEY_PRIORITY_SESSION,
+			PW_KEY_STREAM_NAME,
+			PW_KEY_STREAM_DESCRIPTION,
 			NULL
 		};
 

src/modules/module-session-manager/endpoint.c

@@ -288,6 +288,8 @@ int endpoint_init(struct endpoint *this,
 		PW_KEY_CLIENT_ID,
 		PW_KEY_DEVICE_ID,
 		PW_KEY_MEDIA_CLASS,
+		PW_KEY_ENDPOINT_NAME,
+		PW_KEY_ENDPOINT_ICON_NAME,
 		NULL
 	};