Stream forwarders in the GET object service

[End-rey]

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

We can return the stream from the forwarders, as they can also open it.

Describe the solution you'd like

Stream payload from the forwarder directly to the network.

Describe alternatives you've considered

Keep the object payload in memory.

Additional context

#3466 (comment)

[cthulhu-rider]

as it turned out, payload stream copying is already implemented for GET/RANGE forwarding case. In particular, here

neofs-node/pkg/services/object/get/util.go

Lines 181 to 182 in 08feaae

	obj, err := exec.prm.forwarder(exec.ctx, info, c.client)
	return obj, nil, err

obj is always nil for GET/RANGE

so nothing to do here