Add another suitable agent framework

[g3force]

The agent-runtime is designed for interchangeable agent frameworks. Currently, we only have one implementation that is based on Google ADK (Python), see:

• https://github.com/agentic-layer/agent-template-adk/
• https://github.com/agentic-layer/sdk-python

The main requirements for the framework are:

• Support and expose the A2A API.
• Support configuration of an AI Gateway for LLM calls.
• OTEL Support would also be really useful.

Here are some ideas:

• LangGraph - https://docs.langchain.com/langsmith/server-a2a
• CrewAI - https://docs.crewai.com/en/learn/a2a-agent-delegation
• Microsoft Agent Framework - https://github.com/microsoft/agent-framework/blob/main/python/packages/a2a/README.md
• Google ADK (Java) - https://github.com/google/adk-java/
• Google ADK (Go) - https://github.com/google/adk-go/

Suggestion: Follow the same pattern as for ADK Python. Create a sdk- repo for the framework specific+independent code and a agent-template repository that creates a container with configuration injected in the same way as the agent-template-adk.