Remove GPL decoder unidecode

[Roberts Slisans]

Replacing this line with an alternative would ensure that the entire project is GPL free.

https://github.com/neonbjb/tortoise-tts/blob/main/tortoise/utils/tokenizer.py#L124

Here are some examples of alternatives:

https://stackoverflow.com/a/1211102

https://stackoverflow.com/questions/1207457/convert-a-unicode-string-to-a-string-in-python-containing-extra-symbols/1207479#1207479

Another approach would be to make it an optional dependency with a fallback. While not ideal it would be better than the current situation.

[James Betker]

Happy to approve a PR that makes this replacement.