GitLab

* Introduce WHISPER_MODEL_AUTO_UPDATE env var
* Pass local_files_only to WhisperModel()
* Handle cases where auto-update is disabled but model is non-existent

* Add config variable RAG_EMBEDDING_MODEL_AUTO_UPDATE to control update behavior
* Add RAG utils embedding_model_get_path() function to output the filesystem path in addition to update of the model using huggingface_hub
* Update and utilize existing RAG functions in main: get_embedding_model() & update_embedding_model()
* Add GUI setting to execute manual update process