Support asynchronous execution and logging

[rmadsen-ks]

Long-running shell commands provide no response to the user until they end.

SshCommand command = SshResource.SshClient.CreateCommand(Command);
            var asyncResult = command.BeginExecute();
            var stream = command.OutputStream;
            // read from the stream until the command exits.
            

Related: https://forum.opentap.io/t/ssh-plugin-instability/1188