list: Implement RPC calls for virConnectListAllNetworks

list: Implement RPC calls for virConnectListAllNetworks

The RPC generator doesn't support returning list of object, this patch
do the work manually.

* daemon/remote.c:
  Implemente the server side handler remoteDispatchConnectListAllNetworks.

* src/remote/remote_driver.c:
  Add remote driver handler remoteConnectListAllNetworks.

* src/remote/remote_protocol.x:
  New RPC procedure REMOTE_PROC_CONNECT_LIST_ALL_NETWORKS and
  structs to represent the args and ret for it.

* src/remote_protocol-structs: Likewise.