First draft of gnmi server fork for proto speaking targets

cmd/gnmi-target/oc-target.go

cmd/gnmi-target/target.go

cmd/gnmi-telemetry/telemetry.go

cmd/gnmi/gnmi

cmd/gnmi/gnmi.go

cmd/gnxi/gnoi_target.go

cmd/gnxi/gnxi_target.go

forks/goarista/gnmi/client.go

forks/google/gnmi/model.go

forks/google/gnmi/modeldata/gostruct/gen.go

forks/google/gnmi/modeldata/gostruct/generated.go

forks/google/gnmi/modeldata/modeldata.go

forks/google/gnmi/server.go

forks/google/gnmi/server_test.go

forks/google/gnmi/util.go

go.mod

go.sum

nucleus/gnmi_transport.go