The user uploaded content (images/documents) are now directly
uploaded to S3, and a pre-signed URL is given to the LLM.
The code is a bit complicated because there are behaviors
from docs, other from drive, and in the end some parts are
not used.
This will need some cleanup.
Improvements:
- Allow to upload PDF without vectorized storage (to let
LLM manage them on the fly)
- Allow to configure whether a model can support images/PDF
or not