XTTS Investigation

According to https://docs.coqui.ai/en/stable/models/xtts.html , it supports Chinese.

run this to check:

 tts --model_name tts_models/multilingual/multi-dataset/xtts_v2 \
   --list_language_idx

When it fails download, try to set proxy (pay attention that it's "http" for https_proxy):

$ export https_proxy=http://127.0.0.1:7890
$ export http_proxy=http://127.0.0.1:7890

It needs CUDA GPU to run following demo command:

 tts --model_name tts_models/multilingual/multi-dataset/xtts_v2 \
     --text "It took me quite a long time to develop a voice, and now that I have it I'm not going to be silent." \
     --speaker_idx "Ana Florence" \
     --language_idx en \
     --use_cuda true