The RPC generator doesn't support returning list of object yet, this patch
do the work manually.
* daemon/remote.c:
Implemente the server side handler remoteDispatchConnectListAllNWFilters.
* src/remote/remote_driver.c:
Add remote driver handler remoteConnectListAllNWFilters.
* src/remote/remote_protocol.x:
New RPC procedure REMOTE_PROC_CONNECT_LIST_ALL_NWFILTERS and
structs to represent the args and ret for it.
* src/remote_protocol-structs: Likewise.