core: destroy all resources on hello

Destroy all resources (except the core) for a client when it
does a hello. This typically needs to be done after passing the
connection fd from one client to another.

src/pipewire/private.h

@@ -585,6 +585,8 @@ struct pw_resource {
 	uint32_t type;			/**< type of the client interface */
 	uint32_t version;		/**< version of the client interface */
 
+	unsigned int removed:1;		/**< resource was removed from server */
+
 	struct spa_hook implementation;
 	struct spa_hook_list implementation_list;
 	struct spa_hook_list listener_list;