feat: AnthropicBedrock support ⛰️

[JGalego]

This PR adds support for Anthropic Claude models via Amazon Bedrock.

Since the focus is on consistency, this implementation uses the AnthropicBedrock class (via Anthropic Python SDK) instead of a pure boto3 implementation and introduces minimal code changes.

Example:

python launch_scientist.py --model "bedrock/anthropic.claude-3-sonnet-20240229-v1:0" \
                           --experiment nanoGPT_lite \
                           --num-ideas 2

[conglu1997]

Thank you so much for this, does this already direct Aider queries to Bedrock as well?

[JGalego]

Thank you so much for this, does this already direct Aider queries to Bedrock as well?

Aider uses LiteLLM behind the scenes (Aider-AI/aider#713), so it should work as long as we use the --model "bedrock/<MODEL_ID>" format (check the full list of supported Amazon Bedrock models). I forgot to add the new model choices to launch_oe_scientist.py and perform_writeup.py, but that's all fixed now. One thing to keep in mind though is that AnthropicBedrock expects only the model ID, no prefix (hence all the split's).

[conglu1997]

Thank you! We are grateful for this implementation :)