LangChain Box Data Loader

### Is your feature request related to a problem? Please describe.
LLMs (Large Language Models) with RAG (Retrieval Augmented Generation) access user's own data to generate answers grounded on facts in the user's documents. It would be great to have LangChain data loading interface to Box, so that people can build generative AI applications that can query Box data easily.

### Describe the solution you'd like
LangChain offers custom data loader class for this purpose. It would be great if the Box dev team look into this. List of document types/databases with custom data loader is here:
https://python.langchain.com/docs/integrations/document_loaders/

### Describe alternatives you've considered
Alternatives would be porting Box data locally or copy data to another service that has a LangChain data loader interface.