Update and fix

Server.py : Modified the class section to add optional argument like path to output the audio for the endpoint tss_to_audio speaker_wav is also optional because I added failover mechanism into the tss_funcs.py to failover to reference.wav from finetuned models. So there's this new import : from typing import Optional And created a TTSStreamRequest class because this endpoint was the only one without class. Also modified this line to match the default one in main.py : MODEL_FOLDER = os.getenv('MODEL', 'xtts_models') tts_funcs.py : added this import at the start : import torchaudio.transforms as T I use it to format the audio output to a more standardly used encoding so it can be used widly without degradation So the def local_generation have been widly modified because of this (maybe I should modify the stream_generation in the same manner) in def process_tts_to_file : added a failover mechanism to use the reference.wav from the loaded model if it exist. <!-- This is an auto-generated comment: release notes by coderabbit.ai --> ## Summary by CodeRabbit - **New Features** - Added an option to specify a save path for synthesized audio files. - Introduced a new streaming request capability for text-to-speech (TTS) services. - **Enhancements** - Improved the audio processing and conversion in TTS streaming. - Streamlined the TTS generation process for better performance. - **Bug Fixes** - Fixed an issue with speaker path checks in TTS file generation. - **Refactor** - Refactored TTS generation method for clarity and efficiency. - **Documentation** - Updated README with revised project inspiration, server purpose, and training dataset information. - Simplified installation instructions and added Mantella-specific note. - Expanded Docker usage instructions and acknowledgments in the credit section. <!-- end of auto-generated comment: release notes by coderabbit.ai -->