Native Integration Support for Amazon Bedrock in Google ADK

Hello ADK team,

Thank you for building such an exciting and extensible Agent Development Kit! I'm exploring ways to extend its utility for enterprise-grade use cases and would love to contribute toward integrating Amazon Bedrock as a supported LLM backend within the adk-python framework.

Adding Bedrock as a supported backend could significantly expand ADK’s reach and usability across AWS-first organizations.