chore: add bittensor prediction request tool - using bitapai.io

[DavidMinarsch]

This adapts the prediction_request tool from openai to bittensor, using https://bitapai.io/docs/introduction/.

To test:

from tools.prediction_request_bt import run
kwargs = {"tool": "prediction-offline", "prompt": "What is the weather in Phoenix, Arizona?", "api_keys": {"bitapai": "<YOUR_KEY_HERE>"}}
run(**kwargs)

[DavidMinarsch]

Also looked into this, but again seems to be not working https://python.langchain.com/docs/integrations/llms/bittensor