pulse-server: improve GET_SERVER_INFO

We don't need to bind to the core object again, we can just use the
events on the manager core.
We don't actually have info when the Core is added so don't try to
use it to get defaults for the client.
Use the manager core info in server info.

src/modules/module-protocol-pulse/manager.h

@@ -58,6 +58,8 @@ struct pw_manager {
 	struct pw_core *core;
 	struct pw_registry *registry;
 
+	struct pw_core_info *info;
+
 	uint32_t n_objects;
 	struct spa_list object_list;
 };