Implement methods required for signatures. Receive network map from netmap
storage, convert it to Control service message and return in response.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Add NetmapSnapshot rpc to ControlService protobuf definition. Recompile
proto files. Add required method to server structure.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
