GitLab

* 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

Add COMFYUI and WEBHOOK logging and associated environment variable
control. Add WEBHOOK payload & request debug logs.

This fixes an issue with RAG that stops loading documents as soon
as it reaches a file with unsupported mimetype.

Endpoint role-checking was redundantly applied but FastAPI provides a nice abstraction mechanic...so I applied it. There should be no logical changes in this code; only simpler, cleaner ways for doing the same thing.