Adding set language at run time

[vtikha]

This PR adds the possibility to change the language at run time.

The user is now able to modify the language through the following rpc command. As one is also required to set a corresponding voice , we condensed the command to include both entries in one for ease of use. (Otherwise the user will have to send two distinct commands)

Example of the language switch:

setLanguage en-US en-US-Wavenet-D

by default, the language and voice codes currently supported are the following, but can be easily extended by adding the required entries in the config.ini

languageCodes     en-US it-IT pt-PT fr-FR en-GB

voiceCodes        en-US-Wavenet-A en-US-Wavenet-B en-US-Wavenet-C en-US-Wavenet-D en-US-Wavenet-E en-US-Wavenet-F en-US-Wavenet-G en-US-Wavenet-H en-US-Wavenet-I en-US-Wavenet-J fr-FR-Wavenet-A fr-FR-Wavenet-B fr-FR-Wavenet-C fr-FR-Wavenet-D en-GB-Wavenet-A en-GB-Wavenet-B en-GB-Wavenet-C en-GB-Wavenet-D pt-PT-Wavenet-A pt-PT-Wavenet-B pt-PT-Wavenet-C pt-PT-Wavenet-D it-IT-Wavenet-A it-IT-Wavenet-B it-IT-Wavenet-C it-IT-Wavenet-D

Here is a list of the possible interaction with the module

setLanguage(1:string languageCode, 2:string voiceCode);
setPitch(1:double pitch);
setSpeed(1:double speed);
getLanguageCode();
getVoiceCode();
getPitch();
getSpeed();

cc @randaz81 @Bontempogianpaolo1

[lauracavaliere]

These changes look good to me, thank you.

[ilaria-carlini]

Great work @vtikha! 🚀 LGTM too!

[traversaro]

Perhaps we could to a tag after this PR and release this as part of 2021.05 ?

[vtikha]

Perhaps we could to a tag after this PR and release this as part of 2021.05 ?

Yes, but we have a couple more PRs to do in this repo. Once we finish with the other then for sure

[Bontempogianpaolo1]

Cool! It Looks great!