[Feature request] make cubejs as datasouce of DB-GPT

**Is your feature request related to a problem? Please describe.**
I saw an example of making cubejs and LLM work together [langchain](https://cube.dev/docs/product/configuration/visualization-tools/langchain)
Here is a text-to-sql project based on LLM [DB-GPT](https://github.com/eosphoros-ai/DB-GPT) , I think make cubejs as a datasouce of DB-GPT will be helpful, Will accelerate the maturation of text-to-sql