data: clean up fd and data management

Do not send the offset and size in the add_mem call, just send the
fd and the flags. The area that we need to map from this to find the
meta, chunk and data are sent in a separate call. This should make
it possible to truncate the memory to a larger size to dynamically
allocate more shared memory for a client.
Remove the Id data type, it's not needed.
Don't automatically map memory in remote.c
Pass the original memory type from server to client.
Handle DmaBuf mem in video-play now that the server passed it on.

src/extensions/client-node.h

@@ -405,9 +405,7 @@ struct pw_client_node_proxy_events {
 			      uint32_t mem_id,
 			      uint32_t type,
 			      int memfd,
-			      uint32_t flags,
-			      uint32_t offset,
-			      uint32_t size);
+			      uint32_t flags);
 	/**
 	 * Notify the port of buffers
 	 *