Suggestion: Add Speaker Number and Preview Selected Voice

[Joelson-Forte]

What do you think about adding the Speaker number options for models that have more than one speaker and Preview to hear a preview of the selected voice,?

Similar to this page below.
https://rhasspy.github.io/piper-samples/

I downloaded all the available voices, if you want, just ask and I'll send them to you.

[natlamir]

That looks great. Do you have a Pull Request to add that dropdown and voice preview?