Add support for third-party LLM endpoints

[vishwamartur]

Related to #49

Add support for third-party LLM endpoints, such as Ollama, in the data formulator.

• Backend Changes:

  • Update get_client function in py-src/data_formulator/agents/client_utils.py to handle third-party LLM endpoints using LiteLLM.
  • Add import for LiteLLM in py-src/data_formulator/agents/client_utils.py.

• Frontend Changes:

  • Add UI options for third-party LLM endpoints in src/views/ModelSelectionDialog.tsx.
  • Update the endpoint display logic in src/views/ModelSelectionDialog.tsx to include Ollama.

• Documentation:

  • Add instructions for setting up third-party LLM endpoints in DEVELOPMENT.md.