Added states to googleSpeechProcess, googleSpeech and googleDialog.

[lauracavaliere]

In this PR we did some changes:

• regarding googleSpeech and googleDialog: the /googleSpeech/state:o and the /googleDialog/state:o ports now show different error messages, depending on the type of failure. In particular, in case of network failure the port will output Failure_unavailable. All the possible cases are shown in this documentation;

• regarding googleSpeechProcess: we added some states which describe the current situation of the service:

  • Busy, if the Google request has been launched and the user is waiting for the answer
  • Failure_<StatusCode>, if the Google service fails; the <StatusCode> depends on the type of failure
  • Done, when the Google request terminates successfully
  • Empty which means that the google request ended well but its response is empty

  These states are sent to the /googleSpeechProcess/state:o port only if the state is changed.

[vtikha]

Great! thank you @lauracavaliere @ilaria-carlini