Add studio speakers to open source XTTS!

[WeberJulian]

Add pseudo speaker and language manager to XTTS.
Now these commands work in the CLI:

tts --model_name tts_models/multilingual/multi-dataset/xtts_v2 --list_language_idx
 > tts_models/multilingual/multi-dataset/xtts_v2 is already downloaded.
 > Using model: xtts
 > Available language ids: (Set --language_idx flag to one of these values to use the multi-lingual model.
['en', 'es', 'fr', 'de', 'it', 'pt', 'pl', 'tr', 'ru', 'nl', 'cs', 'ar', 'zh-cn', 'hu', 'ko', 'ja', 'hi']

tts --model_name tts_models/multilingual/multi-dataset/xtts_v2 --list_speaker_idx
 > tts_models/multilingual/multi-dataset/xtts_v2 is already downloaded.
 > Using model: xtts
 > Available speaker ids: (Set --speaker_idx flag to one of these values to use the multi-speaker model.
dict_keys(['Claribel Dervla', 'Daisy Studious', 'Gracie Wise', 'Tammie Ema', 'Alison Dietlinde', 'Ana Florence', 'Annmarie Nele', 'Asya Anara', 'Brenda Stern', 'Gitta Nikolina', 'Henriette Usha', 'Sofia Hellen', 'Tammy Grit', 'Tanja Adelina', 'Vjollca Johnnie', 'Andrew Chipper', 'Badr Odhiambo', 'Dionisio Schuyler', 'Royston Min', 'Viktor Eka', 'Abrahan Mack', 'Adde Michal', 'Baldur Sanjin', 'Craig Gutsy', 'Damien Black', 'Gilberto Mathias', 'Ilkin Urbano', 'Kazuhiko Atallah', 'Ludvig Milivoj', 'Suad Qasim', 'Torcull Diarmuid', 'Viktor Menelaos', 'Zacharie Aimilios', 'Nova Hogarth', 'Maja Ruoho', 'Uta Obando', 'Lidiya Szekeres', 'Chandra MacFarland', 'Szofi Granger', 'Camilla Holmström', 'Lilya Stainthorpe', 'Zofija Kendrick', 'Narelle Moon', 'Barbora MacLean', 'Alexandra Hisakawa', 'Alma María', 'Rosemary Okafor', 'Ige Behringer', 'Filip Traverse', 'Damjan Chapman', 'Wulf Carlevaro', 'Aaron Dreschner', 'Kumar Dahl', 'Eugenio Mataracı', 'Ferran Simen', 'Xavier Hayasaka', 'Luis Moray', 'Marcos Rudaski'])

tts --model_name tts_models/multilingual/multi-dataset/xtts_v2 --speaker_idx 'Ana Florence' --language_idx en --text Hello
 > tts_models/multilingual/multi-dataset/xtts_v2 is already downloaded.
 > Using model: xtts
 > Text: Hello
 > Text splitted to sentences.
['Hello']
 > Processing time: 2.065340518951416
 > Real-time factor: 1.077734722711064
 > Saving output to tts_output.wav

[Edresson]

All looks good to me :)

[Edresson]

@WeberJulian @erogol I added some docs with the new functionalities. Now we can merge it :).

[thpham]

https://coqui.gateway.scarf.sh/hf/bark/text_2.pt