Add ability to set different models for vosk

[chicco-carone]

I just finished setup for vosk using the addon in supervisor and in the config you can only select the language and not the model that is being used. On the vosk site for models lots of languages have multiple models but by default this addon only uses the smallest one but in my experience i would prefer to change it to another one since at least for italian the voice recognition is pretty bad and filled with errors.