refactor all the handlers - folder structure

LLM/language_model.py

LLM/mlx_language_model.py

STT/whisper_stt_handler.py

TTS/melo_handler.py

TTS/parler_handler.py

VAD/vad_handler.py

VAD/vad_iterator.py

connections/local_audio_streamer.py

connections/socket_receiver.py

connections/socket_sender.py

s2s_pipeline.py

utils/thread_manager.py

utils/utils.py