True object response forwarding

[cthulhu-rider]

Is your feature request related to a problem? Please describe.

SN makes excessive decode-encode round of object read responses received from remote SN

Describe the solution you'd like

when SN1 forwards object request to SN2, do:
0. call SN2 over gRPC

1. read response from SN2 gRPC conn into the buffer
2. make necessary protobuf checks trying to avoid unnecessary allocations
3. write same response to client gRPC conn

Describe alternatives you've considered

redirect mechanism. Its effectiveness increases with growth of transferred data, but requires protocol changes

Additional context

#3783