Simplify signal gRpc client

[braginini]

Instead of using sync groups to wait until stream is connected or retry mechanisms try using with grpc.WaitForReady(true)

See examples: https://github.com/grpc/grpc-go/blob/master/examples/features/wait_for_ready/main.go

https://github.com/grpc/grpc-go/blob/master/examples/features/retry/client/main.go